CA2380290C - Method and system for intelligently controlling a remotely located computer - Google Patents
Method and system for intelligently controlling a remotely located computer Download PDFInfo
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- CA2380290C CA2380290C CA002380290A CA2380290A CA2380290C CA 2380290 C CA2380290 C CA 2380290C CA 002380290 A CA002380290 A CA 002380290A CA 2380290 A CA2380290 A CA 2380290A CA 2380290 C CA2380290 C CA 2380290C
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
- G06F3/038—Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F11/00—Error detection; Error correction; Monitoring
- G06F11/22—Detection or location of defective computer hardware by testing during standby operation or during idle time, e.g. start-up testing
- G06F11/2294—Detection or location of defective computer hardware by testing during standby operation or during idle time, e.g. start-up testing by remote test
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/02—Input arrangements using manually operated switches, e.g. using keyboards or dials
- G06F3/023—Arrangements for converting discrete items of information into a coded form, e.g. arrangements for interpreting keyboard generated codes as alphanumeric codes, operand codes or instruction codes
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/14—Digital output to display device ; Cooperation and interconnection of the display device with other functional units
- G06F3/1454—Digital output to display device ; Cooperation and interconnection of the display device with other functional units involving copying of the display data of a local workstation or window to a remote workstation or window so that an actual copy of the data is displayed simultaneously on two or more displays, e.g. teledisplay
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F11/00—Error detection; Error correction; Monitoring
- G06F11/30—Monitoring
- G06F11/34—Recording or statistical evaluation of computer activity, e.g. of down time, of input/output operation ; Recording or statistical evaluation of user activity, e.g. usability assessment
- G06F11/3466—Performance evaluation by tracing or monitoring
- G06F11/3495—Performance evaluation by tracing or monitoring for systems
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
- G09G5/18—Timing circuits for raster scan displays
Abstract
A method and system for remotely accessing and controlling at least one of a target switch (74a) and a target computer (20) using a target controller (50). The video information captured by the target controller (50) is analyzed and compressed in order to reduce network traffic between the target controller (50) and a controlling computer (12).
Description
METHOD AND SYSTEM FOR INTELLIGENTLY CONTROLLING A
REMOTELY LOCATED COMPUTER
BACKGROUND OF THE INVENTION
Field of the Invention The present invention is directed to a method and system for intelligently controlling a remotely located computer. More specifically, the present invention is directed to a control system connected to a video output port and at least one data input port of a computer located in a first location. A user located in a second location, remote from the first location, controls the computer in the first location through the control system as if the user were directly connected to computer at the first location.
Discussion of the Back rg ound Modern computing has migrated away from the use of centralized mainframes to the use of individual (or personal) computers. With that migration has come a decentralization of many of the resources that were centralized in a mainframe environment (e.g., peripheral devices including magnetic or optical disks and their associated files). That decentralization has not been accompanied by an equivalent increase in peer-to-peer networking capabilities such that those decentralized resources are available to a user as the user moves. Moreover, system administration of multiple physically remote systems increases maintenance concerns.
As a result of the lack of peer-to-peer access, a number of systems have been developed to provide control of remote computers. Unfortunately, many of those solutions have provided very limited control of the remote computer. The most rudimentary type of control is a text-based dialup connection. Control of the remote system is then performed through terminal emulation. Control using terminal emulation is also possible through network connections as opposed to dialup connections. Using (1) a telnet server (or daemon) on the remote computer and (2) a telnet client on the local computer, a user can connect to a remote computer -- even across a wide area network (e.g., the Internet).
However, telnet access also is limited by the fact that such control requires additional software (i.e., the server) to be running on the remote computer. Such server software may "crash"
due to the errant operation of the computer. As a result, access to and control of the remote computer is lost after a crash or after a system "hang." In addition, such server software does not begin running on the remote computer until after the boot-up sequence. Thus, it is not possible to watch or alter the boot-up process using a telnet server.
More sophisticated remote control systems include the capability for graphics.
Carbon Copy 32 from Compaq and LapLink from Traveling Software allow for remote - ---- -access of computers while enabling a graphical user interface of the remote computer to be displayed at a user's local computer. Carbon Copy and LapLink on Windows 95, 98, NT and 2000 utilize "hooks" in the display subsystem of the remote computer to capture drawing requests (in the form of GDI calls). Those drawing requests are sent via a communications adapter to a Carbon Copy or LapLink client program running on the local computer. Once -~ -the drawing requests are received locally, the Carbon Copy or LapLink client program "re-executes" the requests so that the drawing operation is performed locally.
Accordingly, the local computer displays both the local and remote images.
In addition, when using Carbon Copy or LapLink in a low to medium bandwidth connection (e.g., a 28.8 K or 56 K modem connection over a telephone line), the amount of data to be transferred becomes an important issue. In such a connection, there is insufficient bandwidth to send a complete copy of the screen frequently. PCAnywhere produced by Symantec of Cupertino, California is an additional remote control program requiring server software on the remote computer in order to transfer graphics between computers.
An alternate graphical control system is the X Windows system, often run on UNIX
workstations. Using X Windows, a server program running on a local computer receives drawing requests from an application running on (i.e., using the CPU and memory resources of) a remote computer. Although it is possible to utilize the X Windows graphical user interface over a wide area network, the X Windows system, like the terminal emulator and Carbon Copy systems, requires that application software be running on the remote computer in order to control the remote computer. That requirement prevents an X
Windows-based system from being able to analyze or modify the boot process of the computers that it controls.
U.S. Patent No: 5,732,212, to Perholtz et al., entitled "SYSTEM AND METHOD
FOR REMOTE MONITORING AND OPERATION OF PERSONAL COMPUTERS,"
discloses a system in which the video, keyboard and mouse ports of a remote computer are connected to a host unit. The host unit may communicate with a local computer via a modem connection over phone lines. As described in the abstract of that patent, the video raster signal is converted to digital form.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide control of a remote computer independent of the operating system of the remote computer.
It is a further object of the present invention to provide a method and system for analyzing the screen information transmitted between the remote control system and the local computer in order to reduce the required bandwidth.
These and other objects of the present invention are provided by a remote control system that connects to a remotely located computer via a video port and one or more data input/output ports (e.g., keyboard, mouse, touch-screen). The system does not utilize resources of the remotely controlled computer, thus, the present invention operates independently of the operating system (and BIOS) of the remotely controlled computer.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will become readily apparent with reference to the following detailed description, particularly when considered in conjunction with the accompanying drawings, in which:
Figures 1A-1 C are block diagrams of a system for accessing and controlling a remotely located target computer system according to the present invention;
Figure 2 is a schematic illustration of the controlling computer of Figure 1A;
Figures 3a through 3c are block diagrams of the relationship between the software and the hardware of several embodiments of the present invention;
Figure 4 is a schematic illustration of a series of uncompressed video signals representing the image generated by the video card of the remote computer;
Figures 5A and 5B are graphical illustrations of the same block of the video memory of Figure 4 between successive image captures by the system of the present invention;
Figure 6 is a schematic illustration of one embodiment of an intelligent video digitizer as shown in Figure 3c;
Figures 7a and 7b are block diagrams showing status registers indicating the status of l 0 blocks of the screen;
Figure 8 is block diagram showing status flags indicating which bits in a block have changed;
Figures 9a and 9b are block diagrams showing compression headers and data for sending incremental changes; and Figure 10 is a block diagram of a circuit for altering the phase of when pixels are sampled.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the diawings, in which like reference numerals designate identical or corresponding parts throughout the several views, Figure 1 A is a block diagram of a system for accessing and controlling a remotely located computer system according to the present invention. In general, the system of the present invention transmits a GDI
representation of digitized video signals as well as mouse and keyboard signals over a communications link.
Since "local" versus "remote" is a matter of perspective, a set of consistent terminology is used throughout this application which ignores relative perspective. Herein, the phrase "target device" refers to a computer or switch that has its video output connected to the digitizer of the present invention. For example, in Figure IA, the computers 20a through 20c are connected through switch 74a. Thus, any of those computers 20, as well as the switch 74a, may be referred to herein as a target device. When referring to a target device that is a computer, that computer herein is referred to as a target computer. Similarly, when referring to a target device that is a switch, that switch is referred to herein as a target switch.
Typically, the target computers are server computers that are connected to a computer network and operate to perform such tasks as controlling the operation of the network, storing commonly used programs or data, or connecting a local area network (LAN) to a wide area network (WAN) (e.g., the Internet). Those computers may be either computers in separate housings or part of a rack-mounted system. In an alternate embodiment, a target computer is a computer that controls any external hardware or equipment (including storage area network, factory equipment or consumer electronics/appliances).
By contrast, the computer that indirectly controls the target device(s) is referred to herein as "the controlling computer." The computer 12 in Figure lA is the controlling computer and is shown in greater detail in Figure 2. Specifically, the computer 12 includes a computer housing-102 that houses a -m-otherboard 104. The motherboard 104 includes a CPU
106 (e.g., Intel 80x86, Motorola 680x0, or PowerPC), memory 108 (e.g., DRAM, ROM, EPROM, EEPROM, SRAM, SDRAM, and Flash RAM), and other optional special purpose logic devices (e.g., ASICs) or configurable logic devices (e.g., GAL and reprogrammable FPGA). The controlling computer 12 also includes plural input devices, (e.g., a keyboard 122 and mouse 124), and a display card 110 for controlling monitor 120. In addition, the computer system 12 further includes magnetic or optical storage devices. Such storage devices include, but are not limited to, a floppy disk drive 114; compact disc reader 118, tape;
and a hard disk 112, any of which are connected using an appropriate device bus (e.g., a SCSI
bus, an Enhanced IDE bus, or an Ultra DMA bus). Also connected to the same device bus or another device bus, the computer 12 may additionally include a compact disc reader/writer unit (not shown) or a compact disc jukebox (not shown). Although a compact disc 119 is shown in a CD caddy, the compact disc 119 can be inserted directly into CD-ROM
drives that do not require caddies. In addition, a printer (not shown) also provides printed listings of operations of the present invention.
As stated above, the system includes at least one computer readable medium.
Examples of computer readable media are compact discs 119, hard disks 112, floppy disks, tape, magneto-optical disks, PROMs (EPROM, EEPROM, Flash EPROM), DRAM, SRAM, SDRAM, etc. Stored on any one or on a combination of computer readable media, the present invention includes software for controlling both the hardware of the computer 12 and for enabling the computer 12 to interact with a human user. Such software may include, but is not limited to, device drivers, operating systems and user applications, such as development tools. Such computer readable media further includes the computer program product of the present invention for remotely accessing and controlling a target computer (or switch). The phrase "computer code devices" as used herein can be either interpreted or executable code mechanisms, including but not limited to scripts, interpreters, dynamic link libraries, subroutines, Java methods and/or classes, and partial or complete executable programs.
Moreover, although portions of the specification describe the operation of portions of the present invention in terms of a microprocessor and a specially programmed memory, one of ordinary skill in the art will appreciate that a portion of or all of those described functions may be implemented in a configurable logic device. Such a logic device may be either a one-time programmable (OTP) logic device or a field programmable gate array (FGPA). It will also be appreciated by one of ordinary skill in the art that a single computer code device and/or logic device may implement more than one of the described functions without departing from the spirit of the present invention.
In addition, in a first embodiment using a "system on a chip," the present invention is implemented as (1) a digital system that includes an integrated microprocessor, memory and specialized logic on a single- or multi-chip module and (2) analog-to-digital and digital-to analog converters. In a second embodiment using a "system on a chip," the present invention is implemented as a mixed-signal system that includes an integrated microprocessor, memory, specialized logic, and analog-to-digital and digital-to analog converters on a single-or multi-chip module. As used herein, "means" will be understood to include any one of the computer code devices, logic devices, and/or systems on a chip, in any combination. That is, although one "means" may be a computer code device, it may interact with another "means"
that is a logic device.
The controlling computer 12 also includes a communications device 53 for communicating with the target device(s). Such a device 53 may include (1) a modem for connecting via a telephone connection, (2) a wireless transceiver for wirelessly communicating, and (3) a wired adapter (e.g., an Ethernet or token ring adapter). In any of those configurations, the controlling computer 12 communicates with a target controller 50 using any selected communications protocol (e.g., TCP/IP, UDP, or RDP). In an alternate embodiment, the controlling computer 12 is a set-top box that receives the output of a target device via a television connection (cable or satellite) and enables the output to be displayed on a television or similar device (e.g., WebTV). Controlling computer 12 can likewise be a notebook, handheld or palm-top computer.
In addition, more than one communications device 53 can be used simultaneously.
For example, two or more communication devices may be combined in parallel in order to increase bandwidth. Moreover, separate adapters may be used for transmitting and receiving.
Moreover, although the controlling computer 12 is illustrated as using a single communications channel, in an alternate embodiment, plural communications channels are used to communicate with plural independent target computers.
Commands or keystrokes entered at the keyboard 122 or mouse 124 of the controlling computer 12 operate to control the target computer 20 as if the command had been entered using a keyboard or mouse that is directly connected to the target computer 20. In addition, the monitor 120 of the controlling computer 12 displays the same video signals that are captured from the video adapter of the target computer 20.
Generally, a target controller 50 is a computer including at least one controller card.
Each controller card is connected to one or more target devices (i.e., computer 20 or switch 74). Each controller card physically connects to at least one set of interfaces including: (1) a video interface 82, (2) a keyboard interface 84 and (3) a mouse interface 86.
In an alternate embodiment, the keyboard and mouse are merged into a single interface (e.g., USB or Macintosh-style). (In an alternate embodiment, one or more interfaces may be wireless, and "connected peripheral devices" as used herein shall refer to wired and wireless peripheral devices.) In addition, the total number of target devices that are logically connected simultaneously may be even greater if the target device is a switch 74a (connected to several target computers 20) rather than a single target computer 20. Moreover, although each of the target computers 20a through 20c is illustrated as having separate housings, the present invention is not limited thereto. More than one target computer may be contained within a single case.
In the embodiment shown in Figure IA, the target controller 50 is implemented as a computer having similar components to the controlling computer 12. Those components include computer code devices for performing portions of the method of the present invention. In the embodiment of Figure 1A, the target controller 50 includes at least one internal "plug-in" or "add-in" card labeled "Controller card 1." In an alternate embodiment, the target controller 50 includes at least one controller integrated onto the motherboard of the computer. In either of those embodiments, the target controller 50 optionally also attaches to local keyboard, mouse and video connections.
In yet another alternate embodiment, the target controller is a stand-alone device similar to a router or a switch. In the router/switch configuration, the keyboard, mouse and screen are not required and the router/switch is configured remotely -- either through the communications device 53 or through a separate control interface (not shown).
Remote configuration may be via a direct connection, a local area network or a wide area network (e.g., the Internet). In addition, the router/switch configuration may be updated through a removable medium (e.g., a floppy disk or CD-ROM) inserted into the router/switch. In the preferred embodiment, the target controller 50 is a computer system running Windows NT (or its successor Windows 2000) and is connected to at least one plug-in card.
Alternate embodiments utilize Windows CE, UNIX, Linux or MacOS as the operating system.
The target controller 50 can be further reduced and integrated into a KVM
switch or into another target device (e.g., integrated on the motherboard of a target computer or included on a peripheral card of the target computer). Illustrative embodiments are shown in Figures 1 B and 1 C.
After configuration, the target controller 50 operates to capture the video output of the target device. The captured video signals are stored in either a frame buffer internal to the controller card or in a memory shared with other components of the computer.
In addition, the controller card 50 fills a set of keyboard/mouse buffers internal to the controller card with keyboard and mouse commands to be sent to the target device. If the target device supports bi-directional mouse and keyboard communication, then the controller card also includes at least one buffer for receiving communications from those devices. Those commands are sent to the controlling computer 12.
The controller 50 includes a video digitizer that receives and converts the analog signals output by connected target device. The controller stores the converted signals in digital form in the video memory (shared with the mother board or dedicated to the controller card) as digital video data. After a configurable amount of processing, the digital video data is sent from the target controller 50 to the controlling computer 12. Based on the desired cost, complexity and performance of the controller, various processing tasks are divided between the hardware and software of the controller 50.
The initial starting point, however, is the pixel depth of the pixels to be rendered on the controlling computer 12. In order to determine that depth, a user must consider both the depth of the target device and the amount of available bandwidth between the controller 50 and the controlling computer 12. If the pixel depth being transferred is low but the pixel depth of the target device is high, then the ability to represent color gradations may be severely impaired. In fact, similar colors that are readily distinguishable on the target device may become indistinguishable on the display of the controlling computer. On the other hand, higher pixel depths require larger amounts of bandwidth to transfer and some loss of color separation may be acceptable.
In one embodiment of the present invention, the controller samples at eight bits per color, providing a 24-bit color sample. In another embodiment, the present invention samples at 5 bits per color to reduce the cost of the A/D converter. The samples are then converted into a bitmap in one of several formats: (1) 8-bits-per-pixel, (2) 16-bits-per-pixel, (3) 24-bits-per pixel, and (4) device independent.
Figure 3a illustrates that, in a first embodiment, the hardware (digitizer 70) and software 230 (including device driver 210 and the digitizer control application 220) of the controller 50 simply act as a thin interface to a remote control software application 200.
When providing the thin interface, neither the software 230 nor the digitizer 70 performs any analysis on the video signals captured by the digitizer 70. Instead, the digitizer control application 220 periodically requests (through the device driver 210) that a whole screen of data be sampTed: The digitizer control application 220 then draws the whole captured screen to its local screen using Windows GDI calls. The remote control software application 200 captures those GDI requests and retransmits them to the controlling computer 12. The client software on the controlling computer 12 then re-executes the commands so that the screen of the controller 50 and the screen of the controlling computer 12 show the same image.
An illustration of an exemplary method of storing the captured/digitized data is shown in Figure 4. In that illustration, the red, green and blue components of each pixel are captured and stored together. In an alternate embodiment, the red, green and blue values are stored separately such that the red value for pixel number 1 is adjacent in memory to the red value for pixel number 2.
Several embodiments are possible for the storage and transmission of the digitized data. It is possible that the data is quantized at one depth (bits-per-pixel), stored at a second depth (greater or less than the quantized depth), and transmitted in a third depth. However, in an alternate embodiment, one or more of those depths may also be the same. In the case of quantizing at 5 bits per color (i.e., 15 bits per pixel), the 15 bits per pixel are converted into a device independent bitmap using 24 bits per pixel. Prior to transmission by LapLink or Carbon Copy, the 24 bits per pixel are converted to a "closest" color in the corresponding color palette (which may be 8 bits per pixel).
Although compression is not required, in this thin-interface embodiment, the preferred remote control software application 200 is LapLink by Traveling Software since, before transmission to the controlling computer 12, LapLink performs some analysis and lossless compression on the image resulting from the captured GDI calls. Accordingly, in that thin-interface embodiment, LapLink can be replaced by any other remote control application but preferably one that also performs lossless compression on the captured GDI
calls before transmission.
In the second embodiment illustrated in Figure 3b, the digitizer 70, the device driver 210, and the remote control software 200 remain consistent with their corresponding parts described in relation to Figure 3a. However, the digitizer control application 220 of Figure 3a is replaced by an analyzing digitizer control application 240. The analyzing digitizer control application 240 requests, through the device driver 210, that a screen be captured (i.e., digitized). Rather than using GDI calls to redraw the entire screen (which would be captured in its entirety by the remote control software 200), the analyzing digitizer control application 240 analyzes the captured image and uses GDI calls to redraw only changed blocks instead.
Those changed blocks are captured by the remote control software 200.
For example, in the preferred embodiment of this implementation, the analyzing digitizer control application 240 partitions a screen into blocks (e.g., 32 pixels by 32 pixels), an example of which is shown in Fig. 5a. Although one embodiment uses fixed size blocks, an alternate embodiment uses blocks of varying size and shape. For example, where large blocks of the screen are a single color, the block size may be increased (e.g., to 64x64 or 128x32) in order to optimize solid block transmission, as is described in greater detail below.
Although any size block can be used, other preferable blocks size are: 16x16, 16x32, 32x16, and 64x 16.
For each block, the analyzing digitizer control application 240 determines if there is a more efficient way to draw a block. One method of drawing a block utilizes identification of solid blocks - i.e., blocks of a single color. In many backgrounds, there exist regions that are a single color (e.g., all blue or all white). Once identified, those blocks can be more efficiently drawn by using a single GDI call indicating that a colored region is to be drawn at a particular (x, y) location on the screen. This method, however, requires that the CPU of the computer system perform the analysis of which blocks are a single color. In a high resolution, 1280x1024 screen using 32x32 blocks, for each screen update, the CPU checks 1280 blocks that are 32x32 pixels each.
The present invention may also identify "solid" blocks which are blocks that probably should have been a single color, but, through errors in digitization, are not exactly one color.
The present invention can be configured to establish (1) a percentage threshold, (2) an intensity threshold or (3) both. The percentage threshold represents the number of errant pixels within a block that can deviate from the "solid" color, regardless of how far from the "solid" color they are, and still treat the block as a solid block. The intensity threshold represents the amount that any pixel can vary from the "solid" color before the block is considered not to be solid. By combining the percentage threshold and the intensity threshold, the system can limit both the number of errant pixels and amount of variation, simultaneously.
Improved performance is not, however, limited to identifying solid-colored blocks.
The analyzing digitizer control application 240 can also improve efficiency by tracking which blocks change between successive screen captures. To track those changes, the analyzing digitizer control application 240 double buffers the digital video information received from the device driver. In this way, the analyzing digitizer control application 240 can compare (1) the screen information stored in a first buffer for a previous frame and (2) the screen information stored in a second buffer for the image currently being captured.
The buffer sizes need not actually be the same sizes as long as the corresponding blocks can be compared in a non-destructive fashion such that the currently captured block can replace the corresponding block from the previous screen after comparison. Having identified the changed blocks, the analyzing digitizer control application 240 then need only redraw the changed areas as they change. The remote control software 200 then captures and transmits those changed blocks.
Unfortunately, as described above, the digitization/quantization process may introduce errors in producing digital data. Those errors not only affect the ability to identify solid blocks, those errors also cause blocks to appear as if they changed when the blocks have actually remained constant. For example, the memory block shown in Figure 5A
represents the data sampled during a first time period. The memory block shown in Figure represents the same block sampled during a subsequent time period. As can be seen, the value in location 500 has changed from 255 to 254. Without further analysis, it would appear that this block has changed. In the illustrated example, the change requires that the block be retransmitted. In all likelihood, the value would change back a short time later and the block would be retransmitted yet again.
To prevent such digitization errors from increasing the amount of data transferred between the target controller 50 and the controlling computer 12, in one embodiment of the analyzing digitizer control application 240, the analyzing digitizer control application 240 filters the sampled data to hide small changes. In a first filtering embodiment, the analyzing digitizer control application 240 stores both the filtered data from a previous image and an unfiltered copy of the previous image. The current image is then captured, stored and a filtered version of the current image is stored separately from the unfiltered version. (It will be appreciated by one of ordinary skill in the art that the entire current image and its filtered equivalent need not be stored. Rather, once the processing of a block (or group of blocks) is complete, the previous block is replaced by the current block, and the area for the "current"
block is reused for the next block.) In one embodiment, a finite impulse response (FIR) filter averages the current pixel's value and the pixel value from the previous frame. That average is then averaged with the previous average from the previous frame. (Rounding (up or down) may be used in light of the division that is inherent in the averaging process.) The two filtered images are compared for changes. If there are changes, then the block is drawn, in either its filtered form or its unfiltered form.
In another filtering embodiment, the analyzing digitizer control application 240 stores a copy of the unfiltered block for a previously sampled screen and calculates differences between the unfiltered block and a currently sampled block. The differences are stored in a difference block, and the difference block is filtered and compared against a threshold (or compared against a threshold and then filtered) to determine if the new block (or portions thereof) should be redrawn. (It will be appreciated by one of ordinary skill in the art that the filtering step may be omitted if the use of a threshold is found to be sufficient to avoid quantization errors.) In any of the above filtering embodiments, the analyzing digitizer control application 240 may actually inadvertently prevent small changes from being transmitted to the controlling computer 12 -- even when the changes are the result of an application's actions.
To prevent the filtering and thresholding from impeding a user's ability to see those small changes, blocks that have changed (but that nonetheless have changed less than the threshold amount before or after filtering), may be sent (in whole or in part) when bandwidth is available. An area of interest may also be designated by the user such that the system ignores changes to sampled data in the area outside of the area of interest.
In one embodiment of the present invention, the filtering of blocks is changed dynamically. For example, the threshold levels may be increased when the user wants to decrease network traffic. In addition, in an alternate embodiment, the system includes a percentage threshold that causes a block not to be treated as changed as long as a total number of pixels within the block that have changed is less than the threshold --regardless of how much those pixels have changed. As a result fewer blocks are treated as "changed" and fewer drawing requests are made. Likewise, the system may change from one block size to another or from one filter to another.
The filtering and thresholding process described above with reference to the analyzing digitizer control application 240, may likewise performed (wholly or partially) in hardware as part of an intelligent digitizer 75 shown in Figure 3c. The intelligent digitizer 75 is shown in greater detail in Figure 6. The video A-to-D/PLL 705 is a triple high speed Analog-to-Digital Converter that contains an integrated PLL, and a serial digital interface for setting individual registers (e.g., registers controlling control the pixel clock and clamping settings). The input signal used by the PLL is the polarized HSYNC (PHSync) signal. This is then multiplied by the value set in one of the internal registers to produce the desired pixel clock frequency. The output is then provided to the Video DSP and PCI FPGAs in order to capture video at the required pixel clock rate. ' In one embodiment of the present invention shown in Figure 10, the system adjusts when the pixel is sampled by adjusting the phase of the A-to-D convertor 705 --i.e., the delay between the active edge of the PHSYNC signal as compared to the first active edge of the sample clock after the active edge of the PHSYNC signal. As shown in Figure 10, in the preferred embodiment, the blue signal from the RGB inputs is used as the positive input to the comparator 1 000a. In alternate embodiments, the red or green signal may be used. In yet another embodiment, two or more of the color signals are combined to form the positive input. As shown in Figure 10, the blue signal is filtered by applying a low threshold signal to the negative input of the comparator 1000a. The filtered blue signal then acts as the clock input of a D flip-flop 1005. The output of the A-to-D converter 705 is the sample clock (shown in Figure 6), which is also applied to the D input of the D flip-flop 1005. The output of the D flip-flop is fed out to the PCI FPGA where its status can be read by the analyzing control application 220 as if the output were part of a register of the FPGA.
In the preferred embodiment, the D flip-flop is included in the CPU Interface CPLD.
In order to control the phase, the analyzing control application 220 reads the status of the output of the D flip-flop 1005 (e.g., once per frame). When the output is a 1, the delay of the A-to-D convertor 705 is moved one unit in a first direction by sending a command to the microprocessor 700 (which then adjusts the delay using the 12C bus).
Conversely, when the output is a 0, the delay is moved one unit in a second direction opposite the first direction. In the A-to-D convertor 705 of the preferred embodiment, each unit corresponds to approximately 11 degrees. In light of this circuit and the fact that the delay is reprogrammed, the system will oscillate between reading a status of 1 and 0. This causes the beginning of pixel data to correlate with the trailing edge of the sample clock signal. As such, the next rising edge of the sample clock signal will be at the center of the period in which the blue signal (and the red and green signals) hold valid data.
In an alternate embodiment, additional smoothing logic (either hardware or software) is used to slow down the changes in phase. Rather than toggling between shifting forward and shifting backward, at each sample, the logic can decide to forego a change after a status read. In order to decide when to change, a running average (or other filtering function) can be used to determine the effect of changing or not changing.
The A-to-D/PLL also has a number of internal registers that allow the board to have control over the phase relationship of the input signals and the output clock signal. This allows adjustments to be made on the sampling clock to ensure that the input signal is sampled on the optimal location and minimize jitter caused by sampling during transition. It also has settings for adjusting the voltage level offset and gain to allow for adjustment due to level shifting and attenuation over the video cable. In the preferred embodiment, the A-to-D/PLL is the Philips TDA875211/8 -- a triple high-speed (100MHz) analog to digital converter. It contains all of the phase-locked-loop circuitry necessary to generate the pixel clock from the Horizontal Sync signal. The TDA8752 has numerous control registers that are set by the microcontroller via an I2C interface.
One set of possible resolutions that can be used by the present invention is shown in Table I below.
7DO~S Verl Fr Horiz. Freq Lines / Frame Ptxels 1 Lme HN LeVetwr~ ; PCLtC PCLK
Freq W Mlus ~' ~70Hz 31.5KHz 450 ??? ??? ??? LOW ! HIGH
x60Hz 31.5KHz 480 / 525 640 / 800 LOW / LOW 25.175MHz 640x480 - 72 72Hz 37.9KHz 480 ! 520 640 / 832 LOW / LOW 31.500MHz 640x480 - 75 75Hz 37.5KHz 480 / 500 640 / 840 LOW / LOW 31.500MHz 640x480 - 85 85Hz 43.3KHz 480 / 509 640 / 832 LOW / LOW 36.000MHz 800x600 - 56 56Hz 35.1 KHz 600 / 625 800 / 1024 HIGH I HIGH 36.000MHz 800x600 - 60 60Hz 37.9KHz 600 / 628 800 / 1056 HIGH / HIGH 40.000MHz 800x600 - 72 72Hz 48.1 KHz 600 / 666 800 / 1040 HIGH / HIGH 50.000MHz 800x600 - 75 75Hz 46.9KHz 600 / 625 800 / 1056 HIGH ! HIGH 49.500MHz 800x600 - 85 85Hz 53.7KHz 600 / 631 800 / 1048 HIGH / HIGH 56.250MHz 1024x768 - 60 60Hz 48.4KHz 768 / 806 1024 / 1344 HIGH / HIGH 65.000MHz 1024x768 - 70 70Hz 56.5KHz 768 / 806 1024 / 1328 HIGH / HIGH 75.000MHz 1024x768 - 75 75Hz 60.0KHz 768 / 800 1024 / 1312 HIGH / HIGH 78.750MHz 1024x768 - 85 85Hz 68.7KHz 768 / 808 1024 / 1376 HIGH / HIGH 194.500MHz Table I
As would be appreciated by one of ordinary skill in the art, other resolutions are possible.
The determination of other possible modes may be aided by reference to VESA
and Industry Standards and Guidelines for Computer Display Monitor Timing, Version 1.0, Revision 0.7, Revision Date: 12/18/96.
In addition to the above factors used to control video modes, the system of the present invention also controls when sampling begins following an (P)HSYNC signal or a VSYNC signal. The time from signal to first sample is called the "front porch." If sampling after an (P)HYSNC signal begins too early (i.e., the front porch is too short), the system will sample "black"
pixels prior to the real left edge of the display. If sampling after an HSYNC signal begins too late (i.e., the from porch is too long), the system will miss sampling the beginning pixels of the display. Similar problems exist for timing with relation to the VSYNC signal. Accordingly, the present invention provides the ability to set the front porch.
In one embodiment of the present invention, the front porch is set manually through user intervention -- typically through a trial and error process. In three automated embodiments, the system of the present invention provides automatic determination of the front porch when a non-black background is used. In the first automated embodiment, the right edge of the screen is used as a reference. Thus, the system uses an initial front porch value, counts out the number of pixels in a row, and then determines if the pixel after the end of the row is black or colored. If that pixel is black using the initial front porch value, then the front porch value is shortened and the counting process is repeated. This shortening process is repeated until a non-black pixel is found in iteration I. Then the front porch value is reverted to the front porch value in iteration I-1 -- i.e., to the front porch value in the previous iteration. On the contrary, if the pixel is colored when using the initial front porch value, then the front porch value is increased until a black pixel is found at the end of a row in iteration I. The front porch value is then reverted to the delay value in iteration I-1 -- i.e., to the front porch value in the previous iteration.
In the second automated embodiment, a process similar to the first automated embodiment is used, except that the beginning of the row is analyzed. If the beginning of the row is found to be black, then the front porch value is increased until a non-black pixel is found in iteration I. Conversely, if the beginning of the row is found to be colored, then the front porch value is decreased until a black pixel is found in iteration I.
Then the front porch value is reverted to the front porch value in iteration I-1.
In a third automated embodiment, the processes of the first and second automated embodiments are combined -- thereby checking the left and right edges. In this manner, the correct number of pixels per line can also be automatically determined. A
similar process can be performed for the vertical delay looking at (1) the top row, (2) the bottom column, or (3) the top and bottom columns.
The Flash memory component(s) contains all non-volatile data required to enable the onboard microprocessor to control operation of the intelligent digitizer 75.
Flash information includes: (1) Microprocessor Program / Backup / Boot code and (2) a PCI FPGA
Initialization Bitstream. If sufficient free memory space exists on the Flash, then the Flash also contains backup copy of the last correctly programmed PCI FPGA
Initialization Bitstream. This enables the digitizer 75 to be reloaded in case of an error in programming.
One embodiment of the Flash configuration uses one PLCC Flash device with a TSOP Flash device soldered on the board.
In one embodiment of the Flash memory device, the memory is physically addressed as a single large memory device. In an alternate embodiment, the memory is physically divided into pages that can be used as the microprocessor decides. By setting the page bits in a page register, the system can change from one page to another. For example, using two page bits, 00= page 0, 01= page 1, 10 = page 2, and 11 = page 3. As the number of page bits increases, the number of independently addressable pages increases. This aids in providing a larger accessible memory to those microprocessors that have small address bus sizes.
The SRAM component contains both User Data to be used for general purpose RAM
and program data when the microprocessor needs to run the program from RAM. In one embodiment of the SRAM memory device, the memory is physically addressed as a single large memory device. In an alternate embodiment, the memory is physically divided into pages as described above.
The CPU Interface CPLD is intended to provide all of the CPU's address/data bus interfacing signals including the chip selects to memory, the FPGA, and any external signals that need to be read from MMIO. By way of a non-limiting example, the FPGAs, CPLD and SDRAM run off a 3.3 volt power supply. The other components may use the same or different supply voltages.
The PCI FPGA provides the communication interface between the CPU of the computer and the local microprocessor 700 onboard the controller 50. Thus, the PCI FPGA
receives requests sent by the device driver 210. It also provides access to the video buffer and supporting registers (e.g., bit change, block status). Although depicted as an FPGA, one of ordinary skill in the art would appreciate that the communication interface also can be either an application specific integrated circuit (ASIC) or a one-time programmable (OTP) circuit if the interface does not need to be field updated. The interface provides the following features (through the device driver 210): (1) re-programming the CPLD over a JTAG
interface; (2) detecting video presence; (3) detecting video resolution parameters; (4) initializing the frame buffer; (5) polarizing sync signals; (6) controlling the Video DSP FPGA; (7) resetting the components of the controller 50; and (8) setting the active video parameters.
The Video DSP FPGA performs most of the video signal processing required to capture, filter, detect changes in frames, and store the video in a frame buffer (e.g., a SyncDRAM memory device). The PCI FPGA controls operation of the video DSP
including any modes that the video DSP has for capturing video.
By providing separate programming interfaces for the two FPGAs, the video DSP
FPGA can be updated without reprogramming the PCI interface that interfaces directly with the PCI bus.
The microprocessor of the controller controls most of the local data flow on the controller 50. That microprocessor performs: (1) Basic system testing (e.g., code checking, FPGA checking, and RAM testing), (2) transferring mouse and keyboard signals, (3) downloading new programs or FPGA boot code; (4) initializing the onboard FPGAs; and (5) communicating with the analog-to-digital converter to control pixel clock settings (e.g., phase and frequency) and video settings (e.g., color offsets). The microprocessor may act as a watchdog timer to ensure that the system is running properly. If the system is not running properly, the microprocessor can then reset the system.
When the controller is first powered on, a power-on reset is performed internally by the CPU. (The RESET pin is held low at power-up by a pull-down resistor until the FPGA is booted. Once booted, the FPGA will drive the signal low unless a reset is asserted by the application). Later, the controller 50 may be reset by receiving a command from the communication interface. This signal forces a hardware reset to the microprocessor and resets the CPU and all registers to a known state. The controller 50 may be partially or completely reset by using commands to perform: (1) a CPU reset, (2) a CPLD reset, or (3) a video DSP
reset. The CPU Reset resets the CPU and the CPLD interface logic to the CPU.
This allows the application to set the CPU and any logic that will affect the operation of the CPU to a known and initial state. In addition, the CPU may have the capability through independent logic to cause a self-reset.
The CPLD reset resets the additional circuitry that does not interface to the CPU. The logic that allows the CPU to reset itself functions independently from the interface logic. In addition, the Video DSP Reset allows either the application or CPU to reset the internal logic of the Video DSP FPGA to either recover from a locked-up or to re-initialize any internal logic that needs to be set to a known state. Preferably, all of the reset signals are active high and are tri-stated with a pull-down resistor. This allows multiple sources to signal a reset without causing contention. An active high reset provides consistency with the CPU's reset polarity.
When the controller 50 determines that the target device is a target switch rather than a target computer, the controller can provide additional functionality specific to the switch.
The controller can provide "thumbnail" images of target computers connected to a target switch to allow many target systems to be displayed at the same time, shown in miniature.
The control appl-icati-ons (220 and 240) ut'rlize a-muiti=window architecture (e:g., the Multiple Document Interface (MDI)) to support control for multiple target devices. When a target computer's window gains focus, the target controller 50 automatically sends the appropriate keystroke sequence (e.g., "<PrtScr> + number + <Enter>") to the switch to select the corresponding switch port of that target computer. When the mouse and keyboard have been inactive for a specified time interval, the controller will optionally enter a scan mode. In this mode, the target-system windows are updated in a repeating sequence. To update each of the target computers, the controller card sends a switch command (i.e., a keystroke sequence (e.g., "<PrtScr> + number + <Enter>")) to select the next target device. The video output of that target device is then sampled, and the sampled image is written using GDI
calls. Any mouse or keyboard activity cancels scan mode, and only the selected target window continues to be updated.
In one embodiment of the system of the present invention, the user (with the help of a configuration file or configuration "wizard") manually establishes the correlation between the name of a system and its switch/port number. In light of the fact that this manual process can be cumbersome, especially when switched are tiered in a hierarchy, an alternate embodiment utilizes an automated configuration process. In that embodiment, the switches utilize one of the keyboard or mouse ports or a separate dedicated communications port to pass information from the target devices or switches up to the target controller 50. In yet another embodiment, the target controller 50 receives configuration information from a network computer about the port/switch configurations.
In a more secure embodiment, the present invention includes security features to restrict the computers that can be viewed or accessed (or both) by the remote control software. For example, using this security, one user may only be able to view target computers on switch ports 1 and 3 while another user can view and interact with computers on switch ports 1 and 2. In this manner, the system of the present invention can provide monitoring capabilities to less trusted individuals and full access to other, trusted individuals.
In an altemate embodiment, two or more different users may connect to the same controller 50. In this embodiment, the two or more users may control different controller cards or may share access to the same controller card. In this embodiment, the captured GDI
calls for a controller card are routed to the appropriate remote control software. Likewise, a user may be connected to multiple controller cards on one or more computers simultaneously.
In that case, the user can monitor and control several target devices simultaneously.
Additional processing performed by the intelligent digitizer 75 is the analysis of the blocks. As shown in Figure 7a, the system maintains at least two status bits per block, although other status bits are also possible. The first status bit indicates which blocks have changed (either with or without filtering). This bit acts as a "dirty" bit in a cache. This bit can be separated into two bits if the system is to track which blocks have changed at all versus which blocks have changed more than the threshold. This threshold may be (1) global for the whole screen or (2) specific to particular blocks. Moreover, this threshold may be updated dynamically either (1) at a user's request or (2) in response to an automatic adjustment of parameters to change performance characteristics.
The second bit illustrated indicates whether the corresponding block is a single color.
As described above, if the block is a single color, then the block can be compressed by redrawing the block as a single GDI call, as discussed above.
As also discussed above, blocks can be compared for similarity to other blocks.
Although not shown in the status fields of Figure 7a, the status fields can include a reference to another block to which the current block is equal.
Figure 7b shows a memory area that can be read by the microprocessor of the controller to determine which blocks have changed or are a single color. If additional bits of status information per block were used, the entry for each block would be widened by that number of bits.
In addition to indicating whether a block has changed, the intelligent digitizer 75 can also, in hardware, track which pixels within a block have changed. When tracking which pixels have changed, a memory area, as shown in Figure 8, is assigned to each block. The analyzing digitizer control application 240 can then read from memory the changed bits and determine if individual pixels should be redrawn of if the block should be redrawn in its entirety. By reading the first 32 bits of that memory and comparing with zero, the system can determine if any pixels in that line have changed. If not, the next line can be processed. In an alternate embodiment, the hardware contains a separate register for each block which identifies which lines within the block have changed. In this way, the system can quickly identify the lines that contain changed pixels.
Although the above description has focused on the normal operation of the present invention, the processing of the system may be paused when a user is temporarily uninterested in the changes on the target device. The analyzing digitizer control application 240 freezes its status in response to a message from the controlling computer.
If the user has minimized the screen representing the target device on the monitor of the controlling computer 12, then real-time updates of changes to the screen are not necessary. The internal -buffersof thecontroller 50-thatrepresent the last screen sent to the controlling computer 12 are no longer updated -- i.e., they are frozen. However, the buffers representing the sampled video signals from the target device continue to be overwritten. The system then continues to track which blocks have changed in comparison to the frozen blocks -- not in comparison to a previously sampled blocks. When the screen is re-enlarged, the controller 50 is unfrozen and the changes are sent back to the controlling computer 12.
Thus, until the screen is un-minimized, the bandwidth that would have been used to send the changes (which would not have been seen) is saved. This is especially important when simultaneously monitoring multiple target devices over a lower-bandwidth modem connection. This method of performing comparison with the frozen blocks still allows the analyzing digitizer control application 240 to inform the controlling computer 12 of how many blocks have changed -- without having to send those changes. Thus, the minimized icon on the controlling computer that represents the target device may flash or an audio signal may be played to inform the user that a major change to the screen has occurred.
In light of the inherent delay in the transmission process, the digitized mouse pointer on a target computer may be updated too slowly to allow accurate control of the mouse. As a result, the controlling computer 12 generates a pseudo-cursor (e.g., a set of cross-hairs) that indicates where the digitized cursor should be. To initialize this process, the digitizer control application 220 (or the analyzing digitizer control application 240) sets the cursor of the target computer to a known location. For example, by sending to the target computer a series of mouse commands, it is possible to drive the cursor to the upper left hand-corner (the 0,0 corner), no matter where the cursor was prior the series of commands. The original cursor is theri forced back dowri to be aligned with the cross-hairs.
As the mouse commands are received by the digitizer control application 220 (or the analyzing digitizer control application 240), they are processed and passed on to the target device (which updates its local cursor). In order to avoid overloading the target computer with mouse packets, the digitizing control application 220 can queue mouse commands and send those mouse conunands as a group. Alternatively, the digitizer control application 220 (or the analyzing digitizer control application 240) can completely filter out a series of mouse movement events. To reproduce the effect that the filtered commands would have had, the system periodically samples the mouse position and sends, to the target controller, a mouse movement command representing the difference between the new position and the previous mouse position.
If the mouse pointer generated at the target controller 50 ever becomes out of alignment with the pointer generated on the target computer, the user can reset the pointers using a hot-key. Like during initialization, the target computer is then sent a series of mouse commands to move the pointer to a known location and then from the known location to the position consistent with the cross-hairs drawn by the digitizer control application 220 (or the analyzing digitizer control application 240). When the window of the digitizing control application 220 has the focus, this re-synchronization process is also performed when the mouse enters an active window of the digitizer control application 220 (or the analyzing digitizer control application 240).
The above discussion has described the present invention in terms of remote control software 200 and an analyzing digitizer control application 240 that are separate software programs. In an alternate embodiment, the functionality of those two programs is more tightly integrated -- either through the use of an API to communicate between them, or by combining the two into a single application. In this tighter integration, the analyzing digitizer control application 240 can transmit the changed blocks to the remote control software 200 in either compressed or uncompressed format. One example of a compressed format is a differential format in which a change flag indicates whether or not each pixel (or line) has changed. Then, the compressed block includes only the values within the block that have changed. Thus, the number of bytes to transmit is reduced as long as the overhead of the flags is less than the number of bytes saved by not transmitting those unchanged pixels in the block.
One implementation of such a compression header is shown in Figure 9a. The header consists of 32 words that are each 32 bits -- one bit for each pixel. As shown in the first line, three pixels in the first 32 pixels are changed. No other pixels in blocks 2-31 are changed, but in the last line, one additional pixel has changed. The data for the four pixels then follows the header.
A second implementation of the compression header utilizes a block header which indicates which lines have changed. The header indicates that only the first and last lines have changed, so the bit flags for those lines are included - without including the bit flags for the unchanged lines.
Another compression technique used in an alternate embodiment includes encoding a block as (1) a reference to a known block (not necessarily the block from the previous screen capture) and (2) the changes that must be made to the referenced block in order to generate the current block. For example, if the background of an application changes, then all blocks identified as part of the background can be changed by simply referencing the first background block. If a portion of the block was not background, then only those parts that are not the background need to be encoded in the block. This technique similarly works for blocks that are almost completely one color. The block is simply encoded as (1) the background color of the block and (2) those pixels that are different from the background color.
In an alternate embodiment, in order to provide even further compression, blocks are compressed using intra-block compression. For example, a block may be compressed using run-length coding (with or without end-of-block markers) or Ziv-Lempel-Welch (LZW) encoding.
Although the target controller 50 has been described above as performing only the screen capture functions, that target controller 50 can provide additional functionality as well.
The digitizer control application 220 and the analyzing digitizer control application 240 can be minimized so that the user can access the other programs stored on the target controller 50.
As such, the target controller 50 can be used to configure the network, cycle power to individual computers (20a to 20c) and any other function that can be performed on computer to which a user is connected. It is even possible that the target controller 50 be connected to one of the switches that it samples.
In yet another embodiment of the present invention, the system captures outputs to a digital display rather than an analog display. In that embodiment, it is not necessary to convert from analog to digital format. The system simply buffers and analyzes the video data as if it were sampled data.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention maybe practiced otherwise than as specifically described herein.
REMOTELY LOCATED COMPUTER
BACKGROUND OF THE INVENTION
Field of the Invention The present invention is directed to a method and system for intelligently controlling a remotely located computer. More specifically, the present invention is directed to a control system connected to a video output port and at least one data input port of a computer located in a first location. A user located in a second location, remote from the first location, controls the computer in the first location through the control system as if the user were directly connected to computer at the first location.
Discussion of the Back rg ound Modern computing has migrated away from the use of centralized mainframes to the use of individual (or personal) computers. With that migration has come a decentralization of many of the resources that were centralized in a mainframe environment (e.g., peripheral devices including magnetic or optical disks and their associated files). That decentralization has not been accompanied by an equivalent increase in peer-to-peer networking capabilities such that those decentralized resources are available to a user as the user moves. Moreover, system administration of multiple physically remote systems increases maintenance concerns.
As a result of the lack of peer-to-peer access, a number of systems have been developed to provide control of remote computers. Unfortunately, many of those solutions have provided very limited control of the remote computer. The most rudimentary type of control is a text-based dialup connection. Control of the remote system is then performed through terminal emulation. Control using terminal emulation is also possible through network connections as opposed to dialup connections. Using (1) a telnet server (or daemon) on the remote computer and (2) a telnet client on the local computer, a user can connect to a remote computer -- even across a wide area network (e.g., the Internet).
However, telnet access also is limited by the fact that such control requires additional software (i.e., the server) to be running on the remote computer. Such server software may "crash"
due to the errant operation of the computer. As a result, access to and control of the remote computer is lost after a crash or after a system "hang." In addition, such server software does not begin running on the remote computer until after the boot-up sequence. Thus, it is not possible to watch or alter the boot-up process using a telnet server.
More sophisticated remote control systems include the capability for graphics.
Carbon Copy 32 from Compaq and LapLink from Traveling Software allow for remote - ---- -access of computers while enabling a graphical user interface of the remote computer to be displayed at a user's local computer. Carbon Copy and LapLink on Windows 95, 98, NT and 2000 utilize "hooks" in the display subsystem of the remote computer to capture drawing requests (in the form of GDI calls). Those drawing requests are sent via a communications adapter to a Carbon Copy or LapLink client program running on the local computer. Once -~ -the drawing requests are received locally, the Carbon Copy or LapLink client program "re-executes" the requests so that the drawing operation is performed locally.
Accordingly, the local computer displays both the local and remote images.
In addition, when using Carbon Copy or LapLink in a low to medium bandwidth connection (e.g., a 28.8 K or 56 K modem connection over a telephone line), the amount of data to be transferred becomes an important issue. In such a connection, there is insufficient bandwidth to send a complete copy of the screen frequently. PCAnywhere produced by Symantec of Cupertino, California is an additional remote control program requiring server software on the remote computer in order to transfer graphics between computers.
An alternate graphical control system is the X Windows system, often run on UNIX
workstations. Using X Windows, a server program running on a local computer receives drawing requests from an application running on (i.e., using the CPU and memory resources of) a remote computer. Although it is possible to utilize the X Windows graphical user interface over a wide area network, the X Windows system, like the terminal emulator and Carbon Copy systems, requires that application software be running on the remote computer in order to control the remote computer. That requirement prevents an X
Windows-based system from being able to analyze or modify the boot process of the computers that it controls.
U.S. Patent No: 5,732,212, to Perholtz et al., entitled "SYSTEM AND METHOD
FOR REMOTE MONITORING AND OPERATION OF PERSONAL COMPUTERS,"
discloses a system in which the video, keyboard and mouse ports of a remote computer are connected to a host unit. The host unit may communicate with a local computer via a modem connection over phone lines. As described in the abstract of that patent, the video raster signal is converted to digital form.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide control of a remote computer independent of the operating system of the remote computer.
It is a further object of the present invention to provide a method and system for analyzing the screen information transmitted between the remote control system and the local computer in order to reduce the required bandwidth.
These and other objects of the present invention are provided by a remote control system that connects to a remotely located computer via a video port and one or more data input/output ports (e.g., keyboard, mouse, touch-screen). The system does not utilize resources of the remotely controlled computer, thus, the present invention operates independently of the operating system (and BIOS) of the remotely controlled computer.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will become readily apparent with reference to the following detailed description, particularly when considered in conjunction with the accompanying drawings, in which:
Figures 1A-1 C are block diagrams of a system for accessing and controlling a remotely located target computer system according to the present invention;
Figure 2 is a schematic illustration of the controlling computer of Figure 1A;
Figures 3a through 3c are block diagrams of the relationship between the software and the hardware of several embodiments of the present invention;
Figure 4 is a schematic illustration of a series of uncompressed video signals representing the image generated by the video card of the remote computer;
Figures 5A and 5B are graphical illustrations of the same block of the video memory of Figure 4 between successive image captures by the system of the present invention;
Figure 6 is a schematic illustration of one embodiment of an intelligent video digitizer as shown in Figure 3c;
Figures 7a and 7b are block diagrams showing status registers indicating the status of l 0 blocks of the screen;
Figure 8 is block diagram showing status flags indicating which bits in a block have changed;
Figures 9a and 9b are block diagrams showing compression headers and data for sending incremental changes; and Figure 10 is a block diagram of a circuit for altering the phase of when pixels are sampled.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the diawings, in which like reference numerals designate identical or corresponding parts throughout the several views, Figure 1 A is a block diagram of a system for accessing and controlling a remotely located computer system according to the present invention. In general, the system of the present invention transmits a GDI
representation of digitized video signals as well as mouse and keyboard signals over a communications link.
Since "local" versus "remote" is a matter of perspective, a set of consistent terminology is used throughout this application which ignores relative perspective. Herein, the phrase "target device" refers to a computer or switch that has its video output connected to the digitizer of the present invention. For example, in Figure IA, the computers 20a through 20c are connected through switch 74a. Thus, any of those computers 20, as well as the switch 74a, may be referred to herein as a target device. When referring to a target device that is a computer, that computer herein is referred to as a target computer. Similarly, when referring to a target device that is a switch, that switch is referred to herein as a target switch.
Typically, the target computers are server computers that are connected to a computer network and operate to perform such tasks as controlling the operation of the network, storing commonly used programs or data, or connecting a local area network (LAN) to a wide area network (WAN) (e.g., the Internet). Those computers may be either computers in separate housings or part of a rack-mounted system. In an alternate embodiment, a target computer is a computer that controls any external hardware or equipment (including storage area network, factory equipment or consumer electronics/appliances).
By contrast, the computer that indirectly controls the target device(s) is referred to herein as "the controlling computer." The computer 12 in Figure lA is the controlling computer and is shown in greater detail in Figure 2. Specifically, the computer 12 includes a computer housing-102 that houses a -m-otherboard 104. The motherboard 104 includes a CPU
106 (e.g., Intel 80x86, Motorola 680x0, or PowerPC), memory 108 (e.g., DRAM, ROM, EPROM, EEPROM, SRAM, SDRAM, and Flash RAM), and other optional special purpose logic devices (e.g., ASICs) or configurable logic devices (e.g., GAL and reprogrammable FPGA). The controlling computer 12 also includes plural input devices, (e.g., a keyboard 122 and mouse 124), and a display card 110 for controlling monitor 120. In addition, the computer system 12 further includes magnetic or optical storage devices. Such storage devices include, but are not limited to, a floppy disk drive 114; compact disc reader 118, tape;
and a hard disk 112, any of which are connected using an appropriate device bus (e.g., a SCSI
bus, an Enhanced IDE bus, or an Ultra DMA bus). Also connected to the same device bus or another device bus, the computer 12 may additionally include a compact disc reader/writer unit (not shown) or a compact disc jukebox (not shown). Although a compact disc 119 is shown in a CD caddy, the compact disc 119 can be inserted directly into CD-ROM
drives that do not require caddies. In addition, a printer (not shown) also provides printed listings of operations of the present invention.
As stated above, the system includes at least one computer readable medium.
Examples of computer readable media are compact discs 119, hard disks 112, floppy disks, tape, magneto-optical disks, PROMs (EPROM, EEPROM, Flash EPROM), DRAM, SRAM, SDRAM, etc. Stored on any one or on a combination of computer readable media, the present invention includes software for controlling both the hardware of the computer 12 and for enabling the computer 12 to interact with a human user. Such software may include, but is not limited to, device drivers, operating systems and user applications, such as development tools. Such computer readable media further includes the computer program product of the present invention for remotely accessing and controlling a target computer (or switch). The phrase "computer code devices" as used herein can be either interpreted or executable code mechanisms, including but not limited to scripts, interpreters, dynamic link libraries, subroutines, Java methods and/or classes, and partial or complete executable programs.
Moreover, although portions of the specification describe the operation of portions of the present invention in terms of a microprocessor and a specially programmed memory, one of ordinary skill in the art will appreciate that a portion of or all of those described functions may be implemented in a configurable logic device. Such a logic device may be either a one-time programmable (OTP) logic device or a field programmable gate array (FGPA). It will also be appreciated by one of ordinary skill in the art that a single computer code device and/or logic device may implement more than one of the described functions without departing from the spirit of the present invention.
In addition, in a first embodiment using a "system on a chip," the present invention is implemented as (1) a digital system that includes an integrated microprocessor, memory and specialized logic on a single- or multi-chip module and (2) analog-to-digital and digital-to analog converters. In a second embodiment using a "system on a chip," the present invention is implemented as a mixed-signal system that includes an integrated microprocessor, memory, specialized logic, and analog-to-digital and digital-to analog converters on a single-or multi-chip module. As used herein, "means" will be understood to include any one of the computer code devices, logic devices, and/or systems on a chip, in any combination. That is, although one "means" may be a computer code device, it may interact with another "means"
that is a logic device.
The controlling computer 12 also includes a communications device 53 for communicating with the target device(s). Such a device 53 may include (1) a modem for connecting via a telephone connection, (2) a wireless transceiver for wirelessly communicating, and (3) a wired adapter (e.g., an Ethernet or token ring adapter). In any of those configurations, the controlling computer 12 communicates with a target controller 50 using any selected communications protocol (e.g., TCP/IP, UDP, or RDP). In an alternate embodiment, the controlling computer 12 is a set-top box that receives the output of a target device via a television connection (cable or satellite) and enables the output to be displayed on a television or similar device (e.g., WebTV). Controlling computer 12 can likewise be a notebook, handheld or palm-top computer.
In addition, more than one communications device 53 can be used simultaneously.
For example, two or more communication devices may be combined in parallel in order to increase bandwidth. Moreover, separate adapters may be used for transmitting and receiving.
Moreover, although the controlling computer 12 is illustrated as using a single communications channel, in an alternate embodiment, plural communications channels are used to communicate with plural independent target computers.
Commands or keystrokes entered at the keyboard 122 or mouse 124 of the controlling computer 12 operate to control the target computer 20 as if the command had been entered using a keyboard or mouse that is directly connected to the target computer 20. In addition, the monitor 120 of the controlling computer 12 displays the same video signals that are captured from the video adapter of the target computer 20.
Generally, a target controller 50 is a computer including at least one controller card.
Each controller card is connected to one or more target devices (i.e., computer 20 or switch 74). Each controller card physically connects to at least one set of interfaces including: (1) a video interface 82, (2) a keyboard interface 84 and (3) a mouse interface 86.
In an alternate embodiment, the keyboard and mouse are merged into a single interface (e.g., USB or Macintosh-style). (In an alternate embodiment, one or more interfaces may be wireless, and "connected peripheral devices" as used herein shall refer to wired and wireless peripheral devices.) In addition, the total number of target devices that are logically connected simultaneously may be even greater if the target device is a switch 74a (connected to several target computers 20) rather than a single target computer 20. Moreover, although each of the target computers 20a through 20c is illustrated as having separate housings, the present invention is not limited thereto. More than one target computer may be contained within a single case.
In the embodiment shown in Figure IA, the target controller 50 is implemented as a computer having similar components to the controlling computer 12. Those components include computer code devices for performing portions of the method of the present invention. In the embodiment of Figure 1A, the target controller 50 includes at least one internal "plug-in" or "add-in" card labeled "Controller card 1." In an alternate embodiment, the target controller 50 includes at least one controller integrated onto the motherboard of the computer. In either of those embodiments, the target controller 50 optionally also attaches to local keyboard, mouse and video connections.
In yet another alternate embodiment, the target controller is a stand-alone device similar to a router or a switch. In the router/switch configuration, the keyboard, mouse and screen are not required and the router/switch is configured remotely -- either through the communications device 53 or through a separate control interface (not shown).
Remote configuration may be via a direct connection, a local area network or a wide area network (e.g., the Internet). In addition, the router/switch configuration may be updated through a removable medium (e.g., a floppy disk or CD-ROM) inserted into the router/switch. In the preferred embodiment, the target controller 50 is a computer system running Windows NT (or its successor Windows 2000) and is connected to at least one plug-in card.
Alternate embodiments utilize Windows CE, UNIX, Linux or MacOS as the operating system.
The target controller 50 can be further reduced and integrated into a KVM
switch or into another target device (e.g., integrated on the motherboard of a target computer or included on a peripheral card of the target computer). Illustrative embodiments are shown in Figures 1 B and 1 C.
After configuration, the target controller 50 operates to capture the video output of the target device. The captured video signals are stored in either a frame buffer internal to the controller card or in a memory shared with other components of the computer.
In addition, the controller card 50 fills a set of keyboard/mouse buffers internal to the controller card with keyboard and mouse commands to be sent to the target device. If the target device supports bi-directional mouse and keyboard communication, then the controller card also includes at least one buffer for receiving communications from those devices. Those commands are sent to the controlling computer 12.
The controller 50 includes a video digitizer that receives and converts the analog signals output by connected target device. The controller stores the converted signals in digital form in the video memory (shared with the mother board or dedicated to the controller card) as digital video data. After a configurable amount of processing, the digital video data is sent from the target controller 50 to the controlling computer 12. Based on the desired cost, complexity and performance of the controller, various processing tasks are divided between the hardware and software of the controller 50.
The initial starting point, however, is the pixel depth of the pixels to be rendered on the controlling computer 12. In order to determine that depth, a user must consider both the depth of the target device and the amount of available bandwidth between the controller 50 and the controlling computer 12. If the pixel depth being transferred is low but the pixel depth of the target device is high, then the ability to represent color gradations may be severely impaired. In fact, similar colors that are readily distinguishable on the target device may become indistinguishable on the display of the controlling computer. On the other hand, higher pixel depths require larger amounts of bandwidth to transfer and some loss of color separation may be acceptable.
In one embodiment of the present invention, the controller samples at eight bits per color, providing a 24-bit color sample. In another embodiment, the present invention samples at 5 bits per color to reduce the cost of the A/D converter. The samples are then converted into a bitmap in one of several formats: (1) 8-bits-per-pixel, (2) 16-bits-per-pixel, (3) 24-bits-per pixel, and (4) device independent.
Figure 3a illustrates that, in a first embodiment, the hardware (digitizer 70) and software 230 (including device driver 210 and the digitizer control application 220) of the controller 50 simply act as a thin interface to a remote control software application 200.
When providing the thin interface, neither the software 230 nor the digitizer 70 performs any analysis on the video signals captured by the digitizer 70. Instead, the digitizer control application 220 periodically requests (through the device driver 210) that a whole screen of data be sampTed: The digitizer control application 220 then draws the whole captured screen to its local screen using Windows GDI calls. The remote control software application 200 captures those GDI requests and retransmits them to the controlling computer 12. The client software on the controlling computer 12 then re-executes the commands so that the screen of the controller 50 and the screen of the controlling computer 12 show the same image.
An illustration of an exemplary method of storing the captured/digitized data is shown in Figure 4. In that illustration, the red, green and blue components of each pixel are captured and stored together. In an alternate embodiment, the red, green and blue values are stored separately such that the red value for pixel number 1 is adjacent in memory to the red value for pixel number 2.
Several embodiments are possible for the storage and transmission of the digitized data. It is possible that the data is quantized at one depth (bits-per-pixel), stored at a second depth (greater or less than the quantized depth), and transmitted in a third depth. However, in an alternate embodiment, one or more of those depths may also be the same. In the case of quantizing at 5 bits per color (i.e., 15 bits per pixel), the 15 bits per pixel are converted into a device independent bitmap using 24 bits per pixel. Prior to transmission by LapLink or Carbon Copy, the 24 bits per pixel are converted to a "closest" color in the corresponding color palette (which may be 8 bits per pixel).
Although compression is not required, in this thin-interface embodiment, the preferred remote control software application 200 is LapLink by Traveling Software since, before transmission to the controlling computer 12, LapLink performs some analysis and lossless compression on the image resulting from the captured GDI calls. Accordingly, in that thin-interface embodiment, LapLink can be replaced by any other remote control application but preferably one that also performs lossless compression on the captured GDI
calls before transmission.
In the second embodiment illustrated in Figure 3b, the digitizer 70, the device driver 210, and the remote control software 200 remain consistent with their corresponding parts described in relation to Figure 3a. However, the digitizer control application 220 of Figure 3a is replaced by an analyzing digitizer control application 240. The analyzing digitizer control application 240 requests, through the device driver 210, that a screen be captured (i.e., digitized). Rather than using GDI calls to redraw the entire screen (which would be captured in its entirety by the remote control software 200), the analyzing digitizer control application 240 analyzes the captured image and uses GDI calls to redraw only changed blocks instead.
Those changed blocks are captured by the remote control software 200.
For example, in the preferred embodiment of this implementation, the analyzing digitizer control application 240 partitions a screen into blocks (e.g., 32 pixels by 32 pixels), an example of which is shown in Fig. 5a. Although one embodiment uses fixed size blocks, an alternate embodiment uses blocks of varying size and shape. For example, where large blocks of the screen are a single color, the block size may be increased (e.g., to 64x64 or 128x32) in order to optimize solid block transmission, as is described in greater detail below.
Although any size block can be used, other preferable blocks size are: 16x16, 16x32, 32x16, and 64x 16.
For each block, the analyzing digitizer control application 240 determines if there is a more efficient way to draw a block. One method of drawing a block utilizes identification of solid blocks - i.e., blocks of a single color. In many backgrounds, there exist regions that are a single color (e.g., all blue or all white). Once identified, those blocks can be more efficiently drawn by using a single GDI call indicating that a colored region is to be drawn at a particular (x, y) location on the screen. This method, however, requires that the CPU of the computer system perform the analysis of which blocks are a single color. In a high resolution, 1280x1024 screen using 32x32 blocks, for each screen update, the CPU checks 1280 blocks that are 32x32 pixels each.
The present invention may also identify "solid" blocks which are blocks that probably should have been a single color, but, through errors in digitization, are not exactly one color.
The present invention can be configured to establish (1) a percentage threshold, (2) an intensity threshold or (3) both. The percentage threshold represents the number of errant pixels within a block that can deviate from the "solid" color, regardless of how far from the "solid" color they are, and still treat the block as a solid block. The intensity threshold represents the amount that any pixel can vary from the "solid" color before the block is considered not to be solid. By combining the percentage threshold and the intensity threshold, the system can limit both the number of errant pixels and amount of variation, simultaneously.
Improved performance is not, however, limited to identifying solid-colored blocks.
The analyzing digitizer control application 240 can also improve efficiency by tracking which blocks change between successive screen captures. To track those changes, the analyzing digitizer control application 240 double buffers the digital video information received from the device driver. In this way, the analyzing digitizer control application 240 can compare (1) the screen information stored in a first buffer for a previous frame and (2) the screen information stored in a second buffer for the image currently being captured.
The buffer sizes need not actually be the same sizes as long as the corresponding blocks can be compared in a non-destructive fashion such that the currently captured block can replace the corresponding block from the previous screen after comparison. Having identified the changed blocks, the analyzing digitizer control application 240 then need only redraw the changed areas as they change. The remote control software 200 then captures and transmits those changed blocks.
Unfortunately, as described above, the digitization/quantization process may introduce errors in producing digital data. Those errors not only affect the ability to identify solid blocks, those errors also cause blocks to appear as if they changed when the blocks have actually remained constant. For example, the memory block shown in Figure 5A
represents the data sampled during a first time period. The memory block shown in Figure represents the same block sampled during a subsequent time period. As can be seen, the value in location 500 has changed from 255 to 254. Without further analysis, it would appear that this block has changed. In the illustrated example, the change requires that the block be retransmitted. In all likelihood, the value would change back a short time later and the block would be retransmitted yet again.
To prevent such digitization errors from increasing the amount of data transferred between the target controller 50 and the controlling computer 12, in one embodiment of the analyzing digitizer control application 240, the analyzing digitizer control application 240 filters the sampled data to hide small changes. In a first filtering embodiment, the analyzing digitizer control application 240 stores both the filtered data from a previous image and an unfiltered copy of the previous image. The current image is then captured, stored and a filtered version of the current image is stored separately from the unfiltered version. (It will be appreciated by one of ordinary skill in the art that the entire current image and its filtered equivalent need not be stored. Rather, once the processing of a block (or group of blocks) is complete, the previous block is replaced by the current block, and the area for the "current"
block is reused for the next block.) In one embodiment, a finite impulse response (FIR) filter averages the current pixel's value and the pixel value from the previous frame. That average is then averaged with the previous average from the previous frame. (Rounding (up or down) may be used in light of the division that is inherent in the averaging process.) The two filtered images are compared for changes. If there are changes, then the block is drawn, in either its filtered form or its unfiltered form.
In another filtering embodiment, the analyzing digitizer control application 240 stores a copy of the unfiltered block for a previously sampled screen and calculates differences between the unfiltered block and a currently sampled block. The differences are stored in a difference block, and the difference block is filtered and compared against a threshold (or compared against a threshold and then filtered) to determine if the new block (or portions thereof) should be redrawn. (It will be appreciated by one of ordinary skill in the art that the filtering step may be omitted if the use of a threshold is found to be sufficient to avoid quantization errors.) In any of the above filtering embodiments, the analyzing digitizer control application 240 may actually inadvertently prevent small changes from being transmitted to the controlling computer 12 -- even when the changes are the result of an application's actions.
To prevent the filtering and thresholding from impeding a user's ability to see those small changes, blocks that have changed (but that nonetheless have changed less than the threshold amount before or after filtering), may be sent (in whole or in part) when bandwidth is available. An area of interest may also be designated by the user such that the system ignores changes to sampled data in the area outside of the area of interest.
In one embodiment of the present invention, the filtering of blocks is changed dynamically. For example, the threshold levels may be increased when the user wants to decrease network traffic. In addition, in an alternate embodiment, the system includes a percentage threshold that causes a block not to be treated as changed as long as a total number of pixels within the block that have changed is less than the threshold --regardless of how much those pixels have changed. As a result fewer blocks are treated as "changed" and fewer drawing requests are made. Likewise, the system may change from one block size to another or from one filter to another.
The filtering and thresholding process described above with reference to the analyzing digitizer control application 240, may likewise performed (wholly or partially) in hardware as part of an intelligent digitizer 75 shown in Figure 3c. The intelligent digitizer 75 is shown in greater detail in Figure 6. The video A-to-D/PLL 705 is a triple high speed Analog-to-Digital Converter that contains an integrated PLL, and a serial digital interface for setting individual registers (e.g., registers controlling control the pixel clock and clamping settings). The input signal used by the PLL is the polarized HSYNC (PHSync) signal. This is then multiplied by the value set in one of the internal registers to produce the desired pixel clock frequency. The output is then provided to the Video DSP and PCI FPGAs in order to capture video at the required pixel clock rate. ' In one embodiment of the present invention shown in Figure 10, the system adjusts when the pixel is sampled by adjusting the phase of the A-to-D convertor 705 --i.e., the delay between the active edge of the PHSYNC signal as compared to the first active edge of the sample clock after the active edge of the PHSYNC signal. As shown in Figure 10, in the preferred embodiment, the blue signal from the RGB inputs is used as the positive input to the comparator 1 000a. In alternate embodiments, the red or green signal may be used. In yet another embodiment, two or more of the color signals are combined to form the positive input. As shown in Figure 10, the blue signal is filtered by applying a low threshold signal to the negative input of the comparator 1000a. The filtered blue signal then acts as the clock input of a D flip-flop 1005. The output of the A-to-D converter 705 is the sample clock (shown in Figure 6), which is also applied to the D input of the D flip-flop 1005. The output of the D flip-flop is fed out to the PCI FPGA where its status can be read by the analyzing control application 220 as if the output were part of a register of the FPGA.
In the preferred embodiment, the D flip-flop is included in the CPU Interface CPLD.
In order to control the phase, the analyzing control application 220 reads the status of the output of the D flip-flop 1005 (e.g., once per frame). When the output is a 1, the delay of the A-to-D convertor 705 is moved one unit in a first direction by sending a command to the microprocessor 700 (which then adjusts the delay using the 12C bus).
Conversely, when the output is a 0, the delay is moved one unit in a second direction opposite the first direction. In the A-to-D convertor 705 of the preferred embodiment, each unit corresponds to approximately 11 degrees. In light of this circuit and the fact that the delay is reprogrammed, the system will oscillate between reading a status of 1 and 0. This causes the beginning of pixel data to correlate with the trailing edge of the sample clock signal. As such, the next rising edge of the sample clock signal will be at the center of the period in which the blue signal (and the red and green signals) hold valid data.
In an alternate embodiment, additional smoothing logic (either hardware or software) is used to slow down the changes in phase. Rather than toggling between shifting forward and shifting backward, at each sample, the logic can decide to forego a change after a status read. In order to decide when to change, a running average (or other filtering function) can be used to determine the effect of changing or not changing.
The A-to-D/PLL also has a number of internal registers that allow the board to have control over the phase relationship of the input signals and the output clock signal. This allows adjustments to be made on the sampling clock to ensure that the input signal is sampled on the optimal location and minimize jitter caused by sampling during transition. It also has settings for adjusting the voltage level offset and gain to allow for adjustment due to level shifting and attenuation over the video cable. In the preferred embodiment, the A-to-D/PLL is the Philips TDA875211/8 -- a triple high-speed (100MHz) analog to digital converter. It contains all of the phase-locked-loop circuitry necessary to generate the pixel clock from the Horizontal Sync signal. The TDA8752 has numerous control registers that are set by the microcontroller via an I2C interface.
One set of possible resolutions that can be used by the present invention is shown in Table I below.
7DO~S Verl Fr Horiz. Freq Lines / Frame Ptxels 1 Lme HN LeVetwr~ ; PCLtC PCLK
Freq W Mlus ~' ~70Hz 31.5KHz 450 ??? ??? ??? LOW ! HIGH
x60Hz 31.5KHz 480 / 525 640 / 800 LOW / LOW 25.175MHz 640x480 - 72 72Hz 37.9KHz 480 ! 520 640 / 832 LOW / LOW 31.500MHz 640x480 - 75 75Hz 37.5KHz 480 / 500 640 / 840 LOW / LOW 31.500MHz 640x480 - 85 85Hz 43.3KHz 480 / 509 640 / 832 LOW / LOW 36.000MHz 800x600 - 56 56Hz 35.1 KHz 600 / 625 800 / 1024 HIGH I HIGH 36.000MHz 800x600 - 60 60Hz 37.9KHz 600 / 628 800 / 1056 HIGH / HIGH 40.000MHz 800x600 - 72 72Hz 48.1 KHz 600 / 666 800 / 1040 HIGH / HIGH 50.000MHz 800x600 - 75 75Hz 46.9KHz 600 / 625 800 / 1056 HIGH ! HIGH 49.500MHz 800x600 - 85 85Hz 53.7KHz 600 / 631 800 / 1048 HIGH / HIGH 56.250MHz 1024x768 - 60 60Hz 48.4KHz 768 / 806 1024 / 1344 HIGH / HIGH 65.000MHz 1024x768 - 70 70Hz 56.5KHz 768 / 806 1024 / 1328 HIGH / HIGH 75.000MHz 1024x768 - 75 75Hz 60.0KHz 768 / 800 1024 / 1312 HIGH / HIGH 78.750MHz 1024x768 - 85 85Hz 68.7KHz 768 / 808 1024 / 1376 HIGH / HIGH 194.500MHz Table I
As would be appreciated by one of ordinary skill in the art, other resolutions are possible.
The determination of other possible modes may be aided by reference to VESA
and Industry Standards and Guidelines for Computer Display Monitor Timing, Version 1.0, Revision 0.7, Revision Date: 12/18/96.
In addition to the above factors used to control video modes, the system of the present invention also controls when sampling begins following an (P)HSYNC signal or a VSYNC signal. The time from signal to first sample is called the "front porch." If sampling after an (P)HYSNC signal begins too early (i.e., the front porch is too short), the system will sample "black"
pixels prior to the real left edge of the display. If sampling after an HSYNC signal begins too late (i.e., the from porch is too long), the system will miss sampling the beginning pixels of the display. Similar problems exist for timing with relation to the VSYNC signal. Accordingly, the present invention provides the ability to set the front porch.
In one embodiment of the present invention, the front porch is set manually through user intervention -- typically through a trial and error process. In three automated embodiments, the system of the present invention provides automatic determination of the front porch when a non-black background is used. In the first automated embodiment, the right edge of the screen is used as a reference. Thus, the system uses an initial front porch value, counts out the number of pixels in a row, and then determines if the pixel after the end of the row is black or colored. If that pixel is black using the initial front porch value, then the front porch value is shortened and the counting process is repeated. This shortening process is repeated until a non-black pixel is found in iteration I. Then the front porch value is reverted to the front porch value in iteration I-1 -- i.e., to the front porch value in the previous iteration. On the contrary, if the pixel is colored when using the initial front porch value, then the front porch value is increased until a black pixel is found at the end of a row in iteration I. The front porch value is then reverted to the delay value in iteration I-1 -- i.e., to the front porch value in the previous iteration.
In the second automated embodiment, a process similar to the first automated embodiment is used, except that the beginning of the row is analyzed. If the beginning of the row is found to be black, then the front porch value is increased until a non-black pixel is found in iteration I. Conversely, if the beginning of the row is found to be colored, then the front porch value is decreased until a black pixel is found in iteration I.
Then the front porch value is reverted to the front porch value in iteration I-1.
In a third automated embodiment, the processes of the first and second automated embodiments are combined -- thereby checking the left and right edges. In this manner, the correct number of pixels per line can also be automatically determined. A
similar process can be performed for the vertical delay looking at (1) the top row, (2) the bottom column, or (3) the top and bottom columns.
The Flash memory component(s) contains all non-volatile data required to enable the onboard microprocessor to control operation of the intelligent digitizer 75.
Flash information includes: (1) Microprocessor Program / Backup / Boot code and (2) a PCI FPGA
Initialization Bitstream. If sufficient free memory space exists on the Flash, then the Flash also contains backup copy of the last correctly programmed PCI FPGA
Initialization Bitstream. This enables the digitizer 75 to be reloaded in case of an error in programming.
One embodiment of the Flash configuration uses one PLCC Flash device with a TSOP Flash device soldered on the board.
In one embodiment of the Flash memory device, the memory is physically addressed as a single large memory device. In an alternate embodiment, the memory is physically divided into pages that can be used as the microprocessor decides. By setting the page bits in a page register, the system can change from one page to another. For example, using two page bits, 00= page 0, 01= page 1, 10 = page 2, and 11 = page 3. As the number of page bits increases, the number of independently addressable pages increases. This aids in providing a larger accessible memory to those microprocessors that have small address bus sizes.
The SRAM component contains both User Data to be used for general purpose RAM
and program data when the microprocessor needs to run the program from RAM. In one embodiment of the SRAM memory device, the memory is physically addressed as a single large memory device. In an alternate embodiment, the memory is physically divided into pages as described above.
The CPU Interface CPLD is intended to provide all of the CPU's address/data bus interfacing signals including the chip selects to memory, the FPGA, and any external signals that need to be read from MMIO. By way of a non-limiting example, the FPGAs, CPLD and SDRAM run off a 3.3 volt power supply. The other components may use the same or different supply voltages.
The PCI FPGA provides the communication interface between the CPU of the computer and the local microprocessor 700 onboard the controller 50. Thus, the PCI FPGA
receives requests sent by the device driver 210. It also provides access to the video buffer and supporting registers (e.g., bit change, block status). Although depicted as an FPGA, one of ordinary skill in the art would appreciate that the communication interface also can be either an application specific integrated circuit (ASIC) or a one-time programmable (OTP) circuit if the interface does not need to be field updated. The interface provides the following features (through the device driver 210): (1) re-programming the CPLD over a JTAG
interface; (2) detecting video presence; (3) detecting video resolution parameters; (4) initializing the frame buffer; (5) polarizing sync signals; (6) controlling the Video DSP FPGA; (7) resetting the components of the controller 50; and (8) setting the active video parameters.
The Video DSP FPGA performs most of the video signal processing required to capture, filter, detect changes in frames, and store the video in a frame buffer (e.g., a SyncDRAM memory device). The PCI FPGA controls operation of the video DSP
including any modes that the video DSP has for capturing video.
By providing separate programming interfaces for the two FPGAs, the video DSP
FPGA can be updated without reprogramming the PCI interface that interfaces directly with the PCI bus.
The microprocessor of the controller controls most of the local data flow on the controller 50. That microprocessor performs: (1) Basic system testing (e.g., code checking, FPGA checking, and RAM testing), (2) transferring mouse and keyboard signals, (3) downloading new programs or FPGA boot code; (4) initializing the onboard FPGAs; and (5) communicating with the analog-to-digital converter to control pixel clock settings (e.g., phase and frequency) and video settings (e.g., color offsets). The microprocessor may act as a watchdog timer to ensure that the system is running properly. If the system is not running properly, the microprocessor can then reset the system.
When the controller is first powered on, a power-on reset is performed internally by the CPU. (The RESET pin is held low at power-up by a pull-down resistor until the FPGA is booted. Once booted, the FPGA will drive the signal low unless a reset is asserted by the application). Later, the controller 50 may be reset by receiving a command from the communication interface. This signal forces a hardware reset to the microprocessor and resets the CPU and all registers to a known state. The controller 50 may be partially or completely reset by using commands to perform: (1) a CPU reset, (2) a CPLD reset, or (3) a video DSP
reset. The CPU Reset resets the CPU and the CPLD interface logic to the CPU.
This allows the application to set the CPU and any logic that will affect the operation of the CPU to a known and initial state. In addition, the CPU may have the capability through independent logic to cause a self-reset.
The CPLD reset resets the additional circuitry that does not interface to the CPU. The logic that allows the CPU to reset itself functions independently from the interface logic. In addition, the Video DSP Reset allows either the application or CPU to reset the internal logic of the Video DSP FPGA to either recover from a locked-up or to re-initialize any internal logic that needs to be set to a known state. Preferably, all of the reset signals are active high and are tri-stated with a pull-down resistor. This allows multiple sources to signal a reset without causing contention. An active high reset provides consistency with the CPU's reset polarity.
When the controller 50 determines that the target device is a target switch rather than a target computer, the controller can provide additional functionality specific to the switch.
The controller can provide "thumbnail" images of target computers connected to a target switch to allow many target systems to be displayed at the same time, shown in miniature.
The control appl-icati-ons (220 and 240) ut'rlize a-muiti=window architecture (e:g., the Multiple Document Interface (MDI)) to support control for multiple target devices. When a target computer's window gains focus, the target controller 50 automatically sends the appropriate keystroke sequence (e.g., "<PrtScr> + number + <Enter>") to the switch to select the corresponding switch port of that target computer. When the mouse and keyboard have been inactive for a specified time interval, the controller will optionally enter a scan mode. In this mode, the target-system windows are updated in a repeating sequence. To update each of the target computers, the controller card sends a switch command (i.e., a keystroke sequence (e.g., "<PrtScr> + number + <Enter>")) to select the next target device. The video output of that target device is then sampled, and the sampled image is written using GDI
calls. Any mouse or keyboard activity cancels scan mode, and only the selected target window continues to be updated.
In one embodiment of the system of the present invention, the user (with the help of a configuration file or configuration "wizard") manually establishes the correlation between the name of a system and its switch/port number. In light of the fact that this manual process can be cumbersome, especially when switched are tiered in a hierarchy, an alternate embodiment utilizes an automated configuration process. In that embodiment, the switches utilize one of the keyboard or mouse ports or a separate dedicated communications port to pass information from the target devices or switches up to the target controller 50. In yet another embodiment, the target controller 50 receives configuration information from a network computer about the port/switch configurations.
In a more secure embodiment, the present invention includes security features to restrict the computers that can be viewed or accessed (or both) by the remote control software. For example, using this security, one user may only be able to view target computers on switch ports 1 and 3 while another user can view and interact with computers on switch ports 1 and 2. In this manner, the system of the present invention can provide monitoring capabilities to less trusted individuals and full access to other, trusted individuals.
In an altemate embodiment, two or more different users may connect to the same controller 50. In this embodiment, the two or more users may control different controller cards or may share access to the same controller card. In this embodiment, the captured GDI
calls for a controller card are routed to the appropriate remote control software. Likewise, a user may be connected to multiple controller cards on one or more computers simultaneously.
In that case, the user can monitor and control several target devices simultaneously.
Additional processing performed by the intelligent digitizer 75 is the analysis of the blocks. As shown in Figure 7a, the system maintains at least two status bits per block, although other status bits are also possible. The first status bit indicates which blocks have changed (either with or without filtering). This bit acts as a "dirty" bit in a cache. This bit can be separated into two bits if the system is to track which blocks have changed at all versus which blocks have changed more than the threshold. This threshold may be (1) global for the whole screen or (2) specific to particular blocks. Moreover, this threshold may be updated dynamically either (1) at a user's request or (2) in response to an automatic adjustment of parameters to change performance characteristics.
The second bit illustrated indicates whether the corresponding block is a single color.
As described above, if the block is a single color, then the block can be compressed by redrawing the block as a single GDI call, as discussed above.
As also discussed above, blocks can be compared for similarity to other blocks.
Although not shown in the status fields of Figure 7a, the status fields can include a reference to another block to which the current block is equal.
Figure 7b shows a memory area that can be read by the microprocessor of the controller to determine which blocks have changed or are a single color. If additional bits of status information per block were used, the entry for each block would be widened by that number of bits.
In addition to indicating whether a block has changed, the intelligent digitizer 75 can also, in hardware, track which pixels within a block have changed. When tracking which pixels have changed, a memory area, as shown in Figure 8, is assigned to each block. The analyzing digitizer control application 240 can then read from memory the changed bits and determine if individual pixels should be redrawn of if the block should be redrawn in its entirety. By reading the first 32 bits of that memory and comparing with zero, the system can determine if any pixels in that line have changed. If not, the next line can be processed. In an alternate embodiment, the hardware contains a separate register for each block which identifies which lines within the block have changed. In this way, the system can quickly identify the lines that contain changed pixels.
Although the above description has focused on the normal operation of the present invention, the processing of the system may be paused when a user is temporarily uninterested in the changes on the target device. The analyzing digitizer control application 240 freezes its status in response to a message from the controlling computer.
If the user has minimized the screen representing the target device on the monitor of the controlling computer 12, then real-time updates of changes to the screen are not necessary. The internal -buffersof thecontroller 50-thatrepresent the last screen sent to the controlling computer 12 are no longer updated -- i.e., they are frozen. However, the buffers representing the sampled video signals from the target device continue to be overwritten. The system then continues to track which blocks have changed in comparison to the frozen blocks -- not in comparison to a previously sampled blocks. When the screen is re-enlarged, the controller 50 is unfrozen and the changes are sent back to the controlling computer 12.
Thus, until the screen is un-minimized, the bandwidth that would have been used to send the changes (which would not have been seen) is saved. This is especially important when simultaneously monitoring multiple target devices over a lower-bandwidth modem connection. This method of performing comparison with the frozen blocks still allows the analyzing digitizer control application 240 to inform the controlling computer 12 of how many blocks have changed -- without having to send those changes. Thus, the minimized icon on the controlling computer that represents the target device may flash or an audio signal may be played to inform the user that a major change to the screen has occurred.
In light of the inherent delay in the transmission process, the digitized mouse pointer on a target computer may be updated too slowly to allow accurate control of the mouse. As a result, the controlling computer 12 generates a pseudo-cursor (e.g., a set of cross-hairs) that indicates where the digitized cursor should be. To initialize this process, the digitizer control application 220 (or the analyzing digitizer control application 240) sets the cursor of the target computer to a known location. For example, by sending to the target computer a series of mouse commands, it is possible to drive the cursor to the upper left hand-corner (the 0,0 corner), no matter where the cursor was prior the series of commands. The original cursor is theri forced back dowri to be aligned with the cross-hairs.
As the mouse commands are received by the digitizer control application 220 (or the analyzing digitizer control application 240), they are processed and passed on to the target device (which updates its local cursor). In order to avoid overloading the target computer with mouse packets, the digitizing control application 220 can queue mouse commands and send those mouse conunands as a group. Alternatively, the digitizer control application 220 (or the analyzing digitizer control application 240) can completely filter out a series of mouse movement events. To reproduce the effect that the filtered commands would have had, the system periodically samples the mouse position and sends, to the target controller, a mouse movement command representing the difference between the new position and the previous mouse position.
If the mouse pointer generated at the target controller 50 ever becomes out of alignment with the pointer generated on the target computer, the user can reset the pointers using a hot-key. Like during initialization, the target computer is then sent a series of mouse commands to move the pointer to a known location and then from the known location to the position consistent with the cross-hairs drawn by the digitizer control application 220 (or the analyzing digitizer control application 240). When the window of the digitizing control application 220 has the focus, this re-synchronization process is also performed when the mouse enters an active window of the digitizer control application 220 (or the analyzing digitizer control application 240).
The above discussion has described the present invention in terms of remote control software 200 and an analyzing digitizer control application 240 that are separate software programs. In an alternate embodiment, the functionality of those two programs is more tightly integrated -- either through the use of an API to communicate between them, or by combining the two into a single application. In this tighter integration, the analyzing digitizer control application 240 can transmit the changed blocks to the remote control software 200 in either compressed or uncompressed format. One example of a compressed format is a differential format in which a change flag indicates whether or not each pixel (or line) has changed. Then, the compressed block includes only the values within the block that have changed. Thus, the number of bytes to transmit is reduced as long as the overhead of the flags is less than the number of bytes saved by not transmitting those unchanged pixels in the block.
One implementation of such a compression header is shown in Figure 9a. The header consists of 32 words that are each 32 bits -- one bit for each pixel. As shown in the first line, three pixels in the first 32 pixels are changed. No other pixels in blocks 2-31 are changed, but in the last line, one additional pixel has changed. The data for the four pixels then follows the header.
A second implementation of the compression header utilizes a block header which indicates which lines have changed. The header indicates that only the first and last lines have changed, so the bit flags for those lines are included - without including the bit flags for the unchanged lines.
Another compression technique used in an alternate embodiment includes encoding a block as (1) a reference to a known block (not necessarily the block from the previous screen capture) and (2) the changes that must be made to the referenced block in order to generate the current block. For example, if the background of an application changes, then all blocks identified as part of the background can be changed by simply referencing the first background block. If a portion of the block was not background, then only those parts that are not the background need to be encoded in the block. This technique similarly works for blocks that are almost completely one color. The block is simply encoded as (1) the background color of the block and (2) those pixels that are different from the background color.
In an alternate embodiment, in order to provide even further compression, blocks are compressed using intra-block compression. For example, a block may be compressed using run-length coding (with or without end-of-block markers) or Ziv-Lempel-Welch (LZW) encoding.
Although the target controller 50 has been described above as performing only the screen capture functions, that target controller 50 can provide additional functionality as well.
The digitizer control application 220 and the analyzing digitizer control application 240 can be minimized so that the user can access the other programs stored on the target controller 50.
As such, the target controller 50 can be used to configure the network, cycle power to individual computers (20a to 20c) and any other function that can be performed on computer to which a user is connected. It is even possible that the target controller 50 be connected to one of the switches that it samples.
In yet another embodiment of the present invention, the system captures outputs to a digital display rather than an analog display. In that embodiment, it is not necessary to convert from analog to digital format. The system simply buffers and analyzes the video data as if it were sampled data.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention maybe practiced otherwise than as specifically described herein.
Claims (21)
1. ~A target controller for remotely controlling an external target server directly or through an external target switch, the target computer producing an analog video output under the supervision of an operating system of the target server, the controller comprising:
an analog video interface for receiving analog video signals from the external target server and receiving said analog video signals independently of the operating system of the target server;
a digitizer for digitizing the analog video signals received from the analog video interface;
a microprocessor;
a memory comprising plural computer code devices including:
a first computer code device configured to divide the digitized video signals into blocks of digitized video;
a second computer code device configured to compare a first block from a first frame to a second block from a subsequent frame; and a third computer code device configured to send only pixel values that changed between the first and second blocks.
an analog video interface for receiving analog video signals from the external target server and receiving said analog video signals independently of the operating system of the target server;
a digitizer for digitizing the analog video signals received from the analog video interface;
a microprocessor;
a memory comprising plural computer code devices including:
a first computer code device configured to divide the digitized video signals into blocks of digitized video;
a second computer code device configured to compare a first block from a first frame to a second block from a subsequent frame; and a third computer code device configured to send only pixel values that changed between the first and second blocks.
2. ~The controller as claimed in claim 1, wherein the third computer code device comprises a fourth computer code device configured to detect if all pixels in a block are a single color such that the block can be redrawn using a single GDI call to fill a block.
3. ~The controller as claimed in claim 1, wherein the second computer code device comprises a fourth computer code device configured to filter each block before determining if the block has changed.
4. ~The controller as claimed in claim 3, wherein the fourth computer code device comprises a fifth computer code device configured to utilize a percentage threshold, wherein the block is not designated as changed if a number of changed pixels within the block is less than the percentage threshold.
5. ~The controller as claimed in claim 3, wherein the fourth computer code device comprises a fifth computer code device configured to utilize an intensity threshold, wherein the block is not designated as changed if a pixel having a maximum change within the block has a change less than the intensity threshold.
6. ~The controller as claimed in claim 1, wherein the analog video interface receives analog video signals from an external target switch, and wherein the first computer code device comprises a fourth computer code device configured to switch a current connection of the external target switch such that the analog video signals change from a first server to a second server.
7. ~The controller as claimed in claim 6, further comprising:
a fifth computer code device configured to capture a mouse click and correlate the mouse click to one of plural windows; and a sixth computer code device configured to convert the mouse click into a series of switch commands that switch the external target switch to an external target server corresponding to the one of plural windows.
a fifth computer code device configured to capture a mouse click and correlate the mouse click to one of plural windows; and a sixth computer code device configured to convert the mouse click into a series of switch commands that switch the external target switch to an external target server corresponding to the one of plural windows.
8. ~The controller as claimed in claim 1, further comprising:
one of a keyboard interface and a mouse interface; and a fourth computer code device configured to send a command received from the one of a keyboard interface and a mouse interface to the at least one of an external target switch and an external target server.
one of a keyboard interface and a mouse interface; and a fourth computer code device configured to send a command received from the one of a keyboard interface and a mouse interface to the at least one of an external target switch and an external target server.
9. ~The controller as claimed in claim 1, further comprising:
an integrated keyboard and mouse interface; and a fourth computer code device configured to send a command received from the integrated keyboard and mouse interface to the external target server.
an integrated keyboard and mouse interface; and a fourth computer code device configured to send a command received from the integrated keyboard and mouse interface to the external target server.
10. The controller as claimed in claim 1, wherein the first computer code device comprises a fourth computer code device configured to dynamically change a size of the blocks of the digitized video.
11. The controller as claimed in claim 3, wherein the fourth computer code device configured to filter each block comprises a fifth computer code device configured to dynamically change a filter used by the fourth computer code device.
12. The controller as claimed in claim 1, wherein the third computer code device comprises a fourth computer code device configured to compress the changed pixel values.
13. The controller as claimed in claim 1, wherein the fourth computer code device comprises a fifth computer code device configured to change a compression technique used by the fourth computer code device.
14. The controller as claimed in claim 1, wherein the first computer code device comprises a fourth computer code device configured to automatically determine a resolution of the analog video signals.
15. The controller as claimed in claim 14, wherein the fourth computer code device further comprises a fifth computer code device configured to determine a delay to be used before sampling each line of video signals.
16. The controller as claimed in claim 1, further comprising a fourth computer code device configured to detect a phase of the analog video signals based on signal jitter and to sample the analog video signals at substantially 180 degrees out of phase to the signal jitter.
17. The controller as claimed in claim 1, further comprising a fourth computer code device configured to track mouse movements and output a pseudo-cursor independent of a digitized cursor.
18. The controller as claimed in claim 17, further comprising a fifth computer code device configured to align the pseudo-cursor and the digitized cursor.
19. A target controller for remotely controlling an external target server producing an analog video output under the supervision of an operating system of the target server, the controller comprising:
an analog video interface for receiving analog video signals from the external target server and receiving said analog video signals independently of an operating condition of the operating system of the target server;
a digitizer for digitizing the analog video signals received from the analog video interface;
a first logic device configured to divide the digitized video signals into blocks of digitized video;
a second logic device configured to compare a first block from a first frame to a second block from a subsequent frame; and a third logic device configured to send only pixel values that changed between the first and second blocks.
an analog video interface for receiving analog video signals from the external target server and receiving said analog video signals independently of an operating condition of the operating system of the target server;
a digitizer for digitizing the analog video signals received from the analog video interface;
a first logic device configured to divide the digitized video signals into blocks of digitized video;
a second logic device configured to compare a first block from a first frame to a second block from a subsequent frame; and a third logic device configured to send only pixel values that changed between the first and second blocks.
20. The controller as claimed in claim 19, wherein the first, second, and third logic devices are implemented as reconfigurable logic devices in a field programmable gate array.
21. A target controller for remotely controlling an external target server producing an analog video output under the supervision of an operating system of the target server, the controller comprising:
an analog video interface for receiving analog video signals from the external target server and receiving said analog video signals independently of the operating system of the target server;
a digitizer for digitizing the analog video signals received from the analog video interface;
first means for dividing the digitized video signals into blocks of digitized video;
second means for comparing a first block from a first frame to a second block from a subsequent frame; and third means for sending only pixel values that changed between the first and second blocks.
an analog video interface for receiving analog video signals from the external target server and receiving said analog video signals independently of the operating system of the target server;
a digitizer for digitizing the analog video signals received from the analog video interface;
first means for dividing the digitized video signals into blocks of digitized video;
second means for comparing a first block from a first frame to a second block from a subsequent frame; and third means for sending only pixel values that changed between the first and second blocks.
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Families Citing this family (295)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5721842A (en) * | 1995-08-25 | 1998-02-24 | Apex Pc Solutions, Inc. | Interconnection system for viewing and controlling remotely connected computers with on-screen video overlay for controlling of the interconnection switch |
US6304895B1 (en) | 1997-08-22 | 2001-10-16 | Apex Inc. | Method and system for intelligently controlling a remotely located computer |
US8631093B2 (en) | 1998-03-19 | 2014-01-14 | Crane Merchandising Systems, Inc. | Remote data acquisition, transmission and analysis system including handheld wireless equipment |
US7167892B2 (en) | 1998-03-19 | 2007-01-23 | Isochron, Inc. | System, method and apparatus for vending machine wireless audit and cashless transaction transport |
DE69935234T2 (en) | 1998-09-22 | 2007-11-08 | Avocent Huntsville Corp., Huntsville | SYSTEM FOR REMOTE ACCESS TO PERSONAL COMPUTER |
US6321335B1 (en) | 1998-10-30 | 2001-11-20 | Acqis Technology, Inc. | Password protected modular computer method and device |
US7266706B2 (en) | 1999-03-03 | 2007-09-04 | Yottayotta, Inc. | Methods and systems for implementing shared disk array management functions |
US7130616B2 (en) * | 2000-04-25 | 2006-10-31 | Simple Devices | System and method for providing content, management, and interactivity for client devices |
US20020013852A1 (en) * | 2000-03-03 | 2002-01-31 | Craig Janik | System for providing content, management, and interactivity for thin client devices |
US7468934B1 (en) * | 1999-07-12 | 2008-12-23 | Ez4Media, Inc. | Clock with link to the internet |
US6538668B1 (en) * | 1999-04-09 | 2003-03-25 | Sun Microsystems, Inc. | Distributed settings control protocol |
US6718415B1 (en) | 1999-05-14 | 2004-04-06 | Acqis Technology, Inc. | Computer system and method including console housing multiple computer modules having independent processing units, mass storage devices, and graphics controllers |
US6643777B1 (en) | 1999-05-14 | 2003-11-04 | Acquis Technology, Inc. | Data security method and device for computer modules |
US6731397B1 (en) * | 1999-05-21 | 2004-05-04 | Foveon, Inc. | Method for storing and retrieving digital image data from an imaging array |
US6263503B1 (en) * | 1999-05-26 | 2001-07-17 | Neal Margulis | Method for effectively implementing a wireless television system |
US8266657B2 (en) | 2001-03-15 | 2012-09-11 | Sling Media Inc. | Method for effectively implementing a multi-room television system |
US6892230B1 (en) * | 1999-06-11 | 2005-05-10 | Microsoft Corporation | Dynamic self-configuration for ad hoc peer networking using mark-up language formated description messages |
US6725281B1 (en) * | 1999-06-11 | 2004-04-20 | Microsoft Corporation | Synchronization of controlled device state using state table and eventing in data-driven remote device control model |
US6378014B1 (en) * | 1999-08-25 | 2002-04-23 | Apex Inc. | Terminal emulator for interfacing between a communications port and a KVM switch |
US20020198961A1 (en) * | 1999-08-27 | 2002-12-26 | Balachander Krishnamurthy | Method for improving web performance by client characterization-driven server adaptation |
US7191168B1 (en) | 1999-08-27 | 2007-03-13 | At&T Corp. | Fast prefix matching of bounded strings |
US7219160B1 (en) | 1999-08-27 | 2007-05-15 | At&T Corp. | Method for fast network-aware clustering |
US7296089B2 (en) * | 1999-08-27 | 2007-11-13 | At&T Corp. | Method for improving web performance by adapting servers based on client cluster characterization |
US6356933B2 (en) | 1999-09-07 | 2002-03-12 | Citrix Systems, Inc. | Methods and apparatus for efficiently transmitting interactive application data between a client and a server using markup language |
US6675193B1 (en) * | 1999-10-29 | 2004-01-06 | Invensys Software Systems | Method and system for remote control of a local system |
US7734744B1 (en) * | 1999-11-09 | 2010-06-08 | Cisco Technology, Inc. | System for communicating management information and method of operation |
US7120692B2 (en) | 1999-12-02 | 2006-10-10 | Senvid, Inc. | Access and control system for network-enabled devices |
US8688797B2 (en) * | 1999-12-02 | 2014-04-01 | Western Digital Technologies, Inc. | Managed peer-to-peer applications, systems and methods for distributed data access and storage |
EP1309901B1 (en) | 1999-12-02 | 2008-05-21 | Western Digital Technologies, Inc. | System for remote recording of television programs |
US8793374B2 (en) * | 1999-12-02 | 2014-07-29 | Western Digital Technologies, Inc. | Managed peer-to-peer applications, systems and methods for distributed data access and storage |
US6775793B2 (en) * | 1999-12-21 | 2004-08-10 | Texas Instruments Incorporated | Data exchange system and method for processors |
AU2001287250A1 (en) * | 2000-03-22 | 2001-10-03 | Yotta Yotta, Inc. | Method and system for providing multimedia information on demand over wide area networks |
WO2001080549A1 (en) * | 2000-04-17 | 2001-10-25 | Koninklijke Philips Electronics N.V. | Arrangement for processing digital video signals in real time |
US6665818B1 (en) * | 2000-04-27 | 2003-12-16 | Hewlett-Packard Development Company, L.P. | Apparatus and method for detecting, diagnosing, and handling deadlock errors |
US6681250B1 (en) * | 2000-05-03 | 2004-01-20 | Avocent Corporation | Network based KVM switching system |
US7010594B2 (en) * | 2000-05-26 | 2006-03-07 | Isochron, Llc | System using environmental sensor and intelligent management and control transceiver for monitoring and controlling remote computing resources |
CA2310538A1 (en) * | 2000-06-09 | 2001-12-09 | Christopher Kirchmann | Data line interrupter switch |
US7117239B1 (en) | 2000-07-28 | 2006-10-03 | Axeda Corporation | Reporting the state of an apparatus to a remote computer |
US6757714B1 (en) * | 2000-07-28 | 2004-06-29 | Axeda Systems Operating Company, Inc. | Reporting the state of an apparatus to a remote computer |
US20020030840A1 (en) * | 2000-09-12 | 2002-03-14 | Fuji Xerox Co., Ltd. | Image output system, and device and method applicable to the same |
US7185014B1 (en) | 2000-09-22 | 2007-02-27 | Axeda Corporation | Retrieving data from a server |
US8108543B2 (en) | 2000-09-22 | 2012-01-31 | Axeda Corporation | Retrieving data from a server |
US6701665B1 (en) * | 2000-10-23 | 2004-03-09 | Phytech Ltd. | Remote phytomonitoring |
US6853841B1 (en) * | 2000-10-25 | 2005-02-08 | Sun Microsystems, Inc. | Protocol for a remote control device to enable control of network attached devices |
US7051084B1 (en) | 2000-11-02 | 2006-05-23 | Citrix Systems, Inc. | Methods and apparatus for regenerating and transmitting a partial page |
US7346842B1 (en) | 2000-11-02 | 2008-03-18 | Citrix Systems, Inc. | Methods and apparatus for incorporating a partial page on a client |
US7194743B2 (en) | 2000-12-12 | 2007-03-20 | Citrix Systems, Inc. | Methods and apparatus for communicating changes between a user interface and an executing application using property paths |
US20020130818A1 (en) * | 2000-12-27 | 2002-09-19 | Viertl John R.M. | Methods and systems for exchanging information, such as nondestructive evaluation data, between distributed users |
US7359949B2 (en) * | 2000-12-29 | 2008-04-15 | Intel Corporation | Remotely controlling a UNIX-based system |
US8206379B2 (en) * | 2001-02-02 | 2012-06-26 | Homer Gregg S | Techniques for alteration of iris pigment |
GB0104835D0 (en) * | 2001-02-27 | 2001-04-18 | Ccc Network Systems Group Ltd | Remote management of computers |
GB0104836D0 (en) * | 2001-02-27 | 2001-04-18 | Ccc Network Systems Group Ltd | Improvements relating to server systems |
WO2002101518A2 (en) * | 2001-03-05 | 2002-12-19 | Anysoft Limited Partnership | Technique for integrating information from one or more remotely located sources |
US20020128041A1 (en) * | 2001-03-09 | 2002-09-12 | Parry Travis J. | Methods and systems for controlling multiple computing devices |
US7143299B1 (en) * | 2001-03-20 | 2006-11-28 | 3Com Corporation | Method for power management of intelligent hardware |
US7424551B2 (en) * | 2001-03-29 | 2008-09-09 | Avocent Corporation | Passive video multiplexing method and apparatus priority to prior provisional application |
JP2002304333A (en) * | 2001-04-03 | 2002-10-18 | Sony Corp | Method and device for transmission |
EP1168009A1 (en) | 2001-04-04 | 2002-01-02 | Agilent Technologies, Inc. (a Delaware corporation) | Light-scattering attenuator |
DE60106137T2 (en) * | 2001-04-12 | 2006-02-23 | Agilent Technologies, Inc. (n.d.Ges.d.Staates Delaware), Palo Alto | Remote data processing administration with display capability |
US7293075B2 (en) * | 2001-04-12 | 2007-11-06 | Unisys Corporation | Method and apparatus for operating a data processing system using multiple console views |
US7248246B2 (en) * | 2001-05-31 | 2007-07-24 | Intel Corporation | Rack mount server with tiltable display |
US7164884B2 (en) | 2001-06-29 | 2007-01-16 | Isochron, Llc | Method and system for interfacing a machine controller and a wireless network |
US7778600B2 (en) | 2001-06-29 | 2010-08-17 | Crane Merchandising Systems, Inc. | Apparatus and method to provide multiple wireless communication paths to and from remotely located equipment |
US6925335B2 (en) * | 2001-07-05 | 2005-08-02 | Isochron, Llc | Real-time alert mechanism for monitoring and controlling field assets via wireless and internet technologies |
US7102691B2 (en) * | 2001-08-08 | 2006-09-05 | Matsushita Electric Industrial Co., Ltd. | Method and apparatus for remote use of personal computer |
US7082200B2 (en) * | 2001-09-06 | 2006-07-25 | Microsoft Corporation | Establishing secure peer networking in trust webs on open networks using shared secret device key |
US7185062B2 (en) * | 2001-09-28 | 2007-02-27 | Emc Corporation | Switch-based storage services |
US20030065864A1 (en) * | 2001-10-03 | 2003-04-03 | Dell Products L.P. | System and method supporting remote data processing system management |
DE10150138B4 (en) * | 2001-10-11 | 2009-10-08 | Siemens Ag | Method for magnetic resonance imaging |
US20030079055A1 (en) * | 2001-10-18 | 2003-04-24 | Inventec Corporation, Taiwan, R.O.C. | Shared input/output network management system |
US7589737B2 (en) * | 2001-10-31 | 2009-09-15 | Hewlett-Packard Development Company, L.P. | System and method for communicating graphics image data over a communication network |
US6957287B2 (en) * | 2001-11-09 | 2005-10-18 | Aten International Co., Ltd. | Asynchronous/synchronous KVMP switch for console and peripheral devices |
US8176226B2 (en) * | 2001-11-09 | 2012-05-08 | Aten International Co., Ltd. | KVMP switch allowing asynchronous and synchronous switching for console devices and peripheral devices among different computers |
US6874060B2 (en) | 2001-12-07 | 2005-03-29 | Dell Products L.P. | Distributed computer system including a virtual disk subsystem and method for providing a virtual local drive |
US6825846B2 (en) * | 2001-12-10 | 2004-11-30 | American Megatrends, Inc. | Systems and methods for capturing screen displays from a host computing system for display at a remote terminal |
US7254601B2 (en) | 2001-12-20 | 2007-08-07 | Questra Corporation | Method and apparatus for managing intelligent assets in a distributed environment |
JP4225777B2 (en) * | 2002-02-08 | 2009-02-18 | シャープ株式会社 | Display device, driving circuit and driving method thereof |
US7398293B2 (en) * | 2002-04-17 | 2008-07-08 | Dell Products L.P. | System and method for using a shared bus for video communications |
US7178149B2 (en) | 2002-04-17 | 2007-02-13 | Axeda Corporation | XML scripting of soap commands |
TWI253567B (en) * | 2002-08-06 | 2006-04-21 | Quanta Comp Inc | Method of remote controlling computers via network and architecture thereof |
US20040133709A1 (en) * | 2002-07-09 | 2004-07-08 | International Business Machines Corporation | Method and system for personalized I/O device initialization |
US7684483B2 (en) * | 2002-08-29 | 2010-03-23 | Raritan Americas, Inc. | Method and apparatus for digitizing and compressing remote video signals |
US7818480B2 (en) * | 2002-08-29 | 2010-10-19 | Raritan Americas, Inc. | Wireless management of remote devices |
US8558795B2 (en) * | 2004-03-12 | 2013-10-15 | Riip, Inc. | Switchless KVM network with wireless technology |
US8068546B2 (en) * | 2002-08-29 | 2011-11-29 | Riip, Inc. | Method and apparatus for transmitting video signals |
US7606314B2 (en) * | 2002-08-29 | 2009-10-20 | Raritan America, Inc. | Method and apparatus for caching, compressing and transmitting video signals |
US20040044822A1 (en) * | 2002-09-03 | 2004-03-04 | Heng-Chien Chen | Computer I/O switching means based on network links |
US7260624B2 (en) * | 2002-09-20 | 2007-08-21 | American Megatrends, Inc. | Systems and methods for establishing interaction between a local computer and a remote computer |
US7321623B2 (en) * | 2002-10-01 | 2008-01-22 | Avocent Corporation | Video compression system |
US20060126718A1 (en) * | 2002-10-01 | 2006-06-15 | Avocent Corporation | Video compression encoder |
US7278047B2 (en) | 2002-10-14 | 2007-10-02 | Lexmark International, Inc. | Providing different clock frequencies for different interfaces of a device |
NL1021652C2 (en) * | 2002-10-15 | 2004-04-16 | Johan Ritser Kuipers | Image generating system, sends digital information from first computer to second computer for loading directly into frame buffer |
US20040093391A1 (en) * | 2002-11-07 | 2004-05-13 | Heng-Chien Chen | Computer console for wirelessly controlling remote computers |
AU2002953335A0 (en) * | 2002-12-11 | 2003-01-09 | Click N Learn Pty Ltd | Computer screen motion capture |
US20040121299A1 (en) * | 2002-12-20 | 2004-06-24 | Electronic Data Systems Corporation | System and method for remote-access virtual-lab environment |
US6875059B2 (en) | 2003-01-15 | 2005-04-05 | American Megatrends, Inc. | In-line remote controllable power switch with integrated power supply |
US20040162992A1 (en) * | 2003-02-19 | 2004-08-19 | Sami Vikash Krishna | Internet privacy protection device |
US7966418B2 (en) | 2003-02-21 | 2011-06-21 | Axeda Corporation | Establishing a virtual tunnel between two computer programs |
US7559092B2 (en) * | 2003-03-04 | 2009-07-07 | Dell Products L.P. | Secured KVM switch |
US7284278B2 (en) * | 2003-03-04 | 2007-10-16 | Dell Products L.P. | Secured KVM switch |
US20040215743A1 (en) * | 2003-03-04 | 2004-10-28 | Soronti, Inc. | Mouse synchronization for virtual presence architecture (VPA) |
US20040215742A1 (en) * | 2003-03-04 | 2004-10-28 | Soronti, Inc. | Image perfection for virtual presence architecture (VPA) |
JP4246528B2 (en) * | 2003-03-26 | 2009-04-02 | 富士通コンポーネント株式会社 | Selector |
US7418141B2 (en) * | 2003-03-31 | 2008-08-26 | American Megatrends, Inc. | Method, apparatus, and computer-readable medium for identifying character coordinates |
TWI224273B (en) * | 2003-04-10 | 2004-11-21 | Inventec Corp | Switching system for operation priority of I/O unit and method thereof |
US6915362B2 (en) * | 2003-04-25 | 2005-07-05 | Dell Products L.P. | System to aggregate keyboard video mouse (KVM) control across multiple server blade chassis |
US7412625B2 (en) * | 2003-05-27 | 2008-08-12 | American Megatrends, Inc. | Method and system for remote software debugging |
US6993620B2 (en) * | 2003-06-13 | 2006-01-31 | Hewlett-Packard Development Company, L.P. | User resource sharing through the USB interface |
US7546584B2 (en) * | 2003-06-16 | 2009-06-09 | American Megatrends, Inc. | Method and system for remote software testing |
US7543277B1 (en) | 2003-06-27 | 2009-06-02 | American Megatrends, Inc. | Method and system for remote software debugging |
US8881023B2 (en) * | 2003-07-07 | 2014-11-04 | Avocent Utah | Methods and apparatus for synchronizing virtual and physical mouse pointers on remote KVM systems |
US9560371B2 (en) | 2003-07-30 | 2017-01-31 | Avocent Corporation | Video compression system |
EP1508851A1 (en) * | 2003-08-18 | 2005-02-23 | Siemens Aktiengesellschaft | Ad hoc image generation method on a screen using a virtual network |
US7529988B1 (en) | 2003-09-02 | 2009-05-05 | Advanced Micro Devices, Inc. | Storage of descriptive information in user defined fields of failure bitmaps in integrated circuit technology development |
JP4075748B2 (en) * | 2003-09-11 | 2008-04-16 | 松下電器産業株式会社 | Image recording device |
US7259482B2 (en) * | 2003-09-24 | 2007-08-21 | Belkin International, Inc. | Distance extender and method making use of same |
US7275212B2 (en) * | 2003-10-23 | 2007-09-25 | Microsoft Corporation | Synchronized graphics and region data for graphics remoting systems |
US20050096086A1 (en) * | 2003-10-31 | 2005-05-05 | Jaalaa, Inc. | Computer interface with both wired and wireless links |
US7246183B2 (en) * | 2003-11-14 | 2007-07-17 | Avocent California Corporation | Phase optimization for wireless KVM transmission |
US7475322B2 (en) * | 2003-11-14 | 2009-01-06 | Avocent Huntsville Corporation | Wireless broadcast protocol |
US8176155B2 (en) | 2003-11-26 | 2012-05-08 | Riip, Inc. | Remote network management system |
US8683024B2 (en) * | 2003-11-26 | 2014-03-25 | Riip, Inc. | System for video digitization and image correction for use with a computer management system |
US8031169B2 (en) * | 2003-12-17 | 2011-10-04 | Riip, Inc. | Automated system and method for high-frequency signal attenuation compensation |
CA2455043A1 (en) * | 2004-01-09 | 2005-07-09 | Digital Multitools Inc. | Method and apparatus for facilitating control of a target computer by a remote computer |
US8429253B1 (en) | 2004-01-27 | 2013-04-23 | Symantec Corporation | Method and system for detecting changes in computer files and settings and automating the migration of settings and files to computers |
ATE399443T1 (en) * | 2004-02-24 | 2008-07-15 | Research In Motion Ltd | METHOD AND SYSTEM FOR REMOTE TESTING A RADIO DEVICE |
US7483694B2 (en) * | 2004-02-24 | 2009-01-27 | Research In Motion Limited | Method and system for remotely testing a wireless device |
US20050193396A1 (en) * | 2004-02-27 | 2005-09-01 | Stafford-Fraser James Q. | Computer network architecture and method of providing display data |
US7827258B1 (en) * | 2004-03-01 | 2010-11-02 | American Megatrends, Inc. | Method, system, and apparatus for communicating with a computer management device |
US20050198245A1 (en) * | 2004-03-06 | 2005-09-08 | John Burgess | Intelligent modular remote server management system |
US7853663B2 (en) * | 2004-03-12 | 2010-12-14 | Riip, Inc. | Wireless management system for control of remote devices |
US20050216620A1 (en) * | 2004-03-26 | 2005-09-29 | Francisc Sandulescu | KVM and USB peripheral switch |
TWI325107B (en) * | 2004-03-30 | 2010-05-21 | Hon Hai Prec Ind Co Ltd | System and method for monitoring graphics interface of remote computer booting |
US7613854B2 (en) * | 2004-04-15 | 2009-11-03 | Aten International Co., Ltd | Keyboard video mouse (KVM) switch wherein peripherals having source communication protocol are routed via KVM switch and converted to destination communication protocol |
TWI273415B (en) * | 2004-05-13 | 2007-02-11 | Aten Int Co Ltd | Control apparatus for controlling a plurality of computers and direct signal collecting device thereof |
US20050273312A1 (en) * | 2004-06-03 | 2005-12-08 | Francisc Sandulescu | Distriubte USB KVM switch |
US20050278284A1 (en) * | 2004-06-04 | 2005-12-15 | International Business Machines Corporation | System and method for accelerating service processor |
US8346605B2 (en) | 2004-06-07 | 2013-01-01 | Sling Media, Inc. | Management of shared media content |
US9998802B2 (en) | 2004-06-07 | 2018-06-12 | Sling Media LLC | Systems and methods for creating variable length clips from a media stream |
US8099755B2 (en) * | 2004-06-07 | 2012-01-17 | Sling Media Pvt. Ltd. | Systems and methods for controlling the encoding of a media stream |
US7975062B2 (en) | 2004-06-07 | 2011-07-05 | Sling Media, Inc. | Capturing and sharing media content |
US7917932B2 (en) | 2005-06-07 | 2011-03-29 | Sling Media, Inc. | Personal video recorder functionality for placeshifting systems |
US7769756B2 (en) | 2004-06-07 | 2010-08-03 | Sling Media, Inc. | Selection and presentation of context-relevant supplemental content and advertising |
EP1769399B1 (en) | 2004-06-07 | 2020-03-18 | Sling Media L.L.C. | Personal media broadcasting system |
JP4342473B2 (en) * | 2004-06-09 | 2009-10-14 | 三洋電機株式会社 | Equipment control system |
US20050278472A1 (en) * | 2004-06-14 | 2005-12-15 | Gierke Justin T | USB extender |
US7457461B2 (en) | 2004-06-25 | 2008-11-25 | Avocent Corporation | Video compression noise immunity |
US7730152B2 (en) * | 2004-06-28 | 2010-06-01 | Broadcom Corporation | Wireless input control of multiple computing devices |
US7519749B1 (en) | 2004-08-25 | 2009-04-14 | American Megatrends, Inc. | Redirecting input and output for multiple computers |
US20060085562A1 (en) * | 2004-10-14 | 2006-04-20 | Blaho Bruce E | Devices and methods for remote computing using a network processor |
US7613927B2 (en) * | 2004-11-12 | 2009-11-03 | Raritan Americas, Inc. | System for providing secure access to KVM switch and other server management systems |
US20060123182A1 (en) * | 2004-12-07 | 2006-06-08 | Francisc Sandulescu | Distributed KVM and peripheral switch |
US8935316B2 (en) | 2005-01-14 | 2015-01-13 | Citrix Systems, Inc. | Methods and systems for in-session playback on a local machine of remotely-stored and real time presentation layer protocol data |
US20060159432A1 (en) | 2005-01-14 | 2006-07-20 | Citrix Systems, Inc. | System and methods for automatic time-warped playback in rendering a recorded computer session |
US7996549B2 (en) * | 2005-01-14 | 2011-08-09 | Citrix Systems, Inc. | Methods and systems for recording and real-time playback of presentation layer protocol data |
US8200828B2 (en) | 2005-01-14 | 2012-06-12 | Citrix Systems, Inc. | Systems and methods for single stack shadowing |
US8340130B2 (en) | 2005-01-14 | 2012-12-25 | Citrix Systems, Inc. | Methods and systems for generating playback instructions for rendering of a recorded computer session |
US8296441B2 (en) | 2005-01-14 | 2012-10-23 | Citrix Systems, Inc. | Methods and systems for joining a real-time session of presentation layer protocol data |
US7831728B2 (en) * | 2005-01-14 | 2010-11-09 | Citrix Systems, Inc. | Methods and systems for real-time seeking during real-time playback of a presentation layer protocol data stream |
US8145777B2 (en) | 2005-01-14 | 2012-03-27 | Citrix Systems, Inc. | Method and system for real-time seeking during playback of remote presentation protocols |
US20060161671A1 (en) * | 2005-01-14 | 2006-07-20 | Citrix Systems, Inc. | Method and systems for capture and replay of remote presentation protocol data |
US8230096B2 (en) | 2005-01-14 | 2012-07-24 | Citrix Systems, Inc. | Methods and systems for generating playback instructions for playback of a recorded computer session |
JP4513592B2 (en) * | 2005-02-09 | 2010-07-28 | 日本電気株式会社 | Computer switching device, computer switching method used therefor, and program therefor |
JP4625346B2 (en) * | 2005-02-25 | 2011-02-02 | 株式会社リコー | Information processing system |
US9213519B2 (en) * | 2005-02-28 | 2015-12-15 | Hewlett-Packard Development Company L.P. | Systems and methods for evaluating the operation of a multi-node graphics system |
US7516255B1 (en) | 2005-03-30 | 2009-04-07 | Teradici Corporation | Method and apparatus for providing a low-latency connection between a data processor and a remote graphical user interface over a network |
US8560753B1 (en) | 2005-03-30 | 2013-10-15 | Teradici Corporation | Method and apparatus for remote input/output in a computer system |
US7451301B2 (en) * | 2005-03-30 | 2008-11-11 | Intel Corporation | OS independent device management methods and apparatuses having a map providing codes for various activations of keys |
US7982757B2 (en) * | 2005-04-01 | 2011-07-19 | Digital Multitools Inc. | Method for reducing noise and jitter effects in KVM systems |
US7908335B1 (en) | 2005-04-06 | 2011-03-15 | Teradici Corporation | Methods and apparatus for bridging a USB connection |
US7676605B1 (en) | 2005-04-06 | 2010-03-09 | Teradici Corporation | Methods and apparatus for bridging a bus controller |
US11733958B2 (en) | 2005-05-05 | 2023-08-22 | Iii Holdings 1, Llc | Wireless mesh-enabled system, host device, and method for use therewith |
US20060282855A1 (en) * | 2005-05-05 | 2006-12-14 | Digital Display Innovations, Llc | Multiple remote display system |
US20060253639A1 (en) * | 2005-05-05 | 2006-11-09 | Aten International Co., Ltd. | Control system for controlling a plurality of target computers through portable computer |
US8200796B1 (en) | 2005-05-05 | 2012-06-12 | Digital Display Innovations, Llc | Graphics display system for multiple remote terminals |
US8019883B1 (en) | 2005-05-05 | 2011-09-13 | Digital Display Innovations, Llc | WiFi peripheral mode display system |
US7667707B1 (en) | 2005-05-05 | 2010-02-23 | Digital Display Innovations, Llc | Computer system for supporting multiple remote displays |
US7702952B2 (en) | 2005-06-30 | 2010-04-20 | Sling Media, Inc. | Firmware update for consumer electronic device |
ITMI20051358A1 (en) * | 2005-07-15 | 2007-01-16 | Babel S R L | DEVICE SHARING DEVICE IN A HIGH-RELIABILITY IT SYSTEM |
US8107527B1 (en) | 2005-07-28 | 2012-01-31 | Teradici Corporation | Progressive block encoding using region analysis |
US8345768B1 (en) | 2005-07-28 | 2013-01-01 | Teradici Corporation | Progressive block encoding using region analysis |
US7822278B1 (en) | 2005-09-20 | 2010-10-26 | Teradici Corporation | Methods and apparatus for encoding a digital video signal |
US7634076B2 (en) * | 2005-08-03 | 2009-12-15 | Indicium Media, Llc | Network, system and method for distributing digital media |
US7886091B2 (en) * | 2005-08-05 | 2011-02-08 | Global Serv Inc. | Methods and arrangements for performing desktop switching |
US7546374B2 (en) | 2005-08-05 | 2009-06-09 | Global Serv Inc. | Methods and arrangements for managing and maintaining a switch environment |
US7689704B2 (en) | 2005-08-05 | 2010-03-30 | Global Serv Inc. | Methods and arrangements for managing automated switching |
US20070076963A1 (en) * | 2005-09-30 | 2007-04-05 | Wellsyn Technology, Inc. | Image transmission mechanism and method for implementing the same |
US8478884B2 (en) | 2005-09-30 | 2013-07-02 | Riip, Inc. | Wireless remote device management utilizing mesh topology |
US8191008B2 (en) | 2005-10-03 | 2012-05-29 | Citrix Systems, Inc. | Simulating multi-monitor functionality in a single monitor environment |
US7752339B2 (en) * | 2005-10-11 | 2010-07-06 | Aten International Co., Ltd. | Matrix architecture for KVM extenders |
US8319728B2 (en) * | 2005-10-17 | 2012-11-27 | Avocent Huntsville Corporation | Input-device movement to cursor movement correlator |
US7899864B2 (en) * | 2005-11-01 | 2011-03-01 | Microsoft Corporation | Multi-user terminal services accelerator |
US20070112906A1 (en) * | 2005-11-15 | 2007-05-17 | Microsoft Corporation | Infrastructure for multi-modal multilingual communications devices |
WO2007057053A1 (en) * | 2005-11-21 | 2007-05-24 | Agilent Technologies, Inc. | Conditional updating of image data in a memory buffer |
US8112513B2 (en) * | 2005-11-30 | 2012-02-07 | Microsoft Corporation | Multi-user display proxy server |
US8010843B2 (en) * | 2005-12-14 | 2011-08-30 | American Megatrends, Inc. | System and method for debugging a target computer using SMBus |
US7423642B2 (en) * | 2005-12-14 | 2008-09-09 | Winbond Electronics Corporation | Efficient video frame capturing |
US7441063B2 (en) * | 2005-12-14 | 2008-10-21 | Aten International Co., Ltd. | KVM system for controlling computers and method thereof |
US8484068B2 (en) | 2005-12-14 | 2013-07-09 | Crane Merchandising Systems, Inc. | Method and system for evaluating consumer demand for multiple products and services at remotely located equipment |
US7924884B2 (en) * | 2005-12-20 | 2011-04-12 | Citrix Systems, Inc. | Performance logging using relative differentials and skip recording |
US7555570B2 (en) | 2006-02-17 | 2009-06-30 | Avocent Huntsville Corporation | Device and method for configuring a target device |
US7689677B2 (en) * | 2006-02-17 | 2010-03-30 | Avocent Huntsville Corporation | Dynamic power cycling |
US8718147B2 (en) * | 2006-02-17 | 2014-05-06 | Avocent Huntsville Corporation | Video compression algorithm |
EP2267972A1 (en) * | 2006-02-21 | 2010-12-29 | BrainLAB AG | Computer network system and method for operating the network system screenshot and sourceshot control |
US20070200858A1 (en) * | 2006-02-28 | 2007-08-30 | Aten International Co., Ltd | KVM switch and a computer switching method |
US7852873B2 (en) * | 2006-03-01 | 2010-12-14 | Lantronix, Inc. | Universal computer management interface |
US7782961B2 (en) * | 2006-04-28 | 2010-08-24 | Avocent Corporation | DVC delta commands |
US7493912B2 (en) * | 2006-06-09 | 2009-02-24 | Hartman Brian T | Fixed cone sleeve valve having cone supported by means downstream of the gate in its closed position |
US20070300051A1 (en) * | 2006-06-26 | 2007-12-27 | Rothman Michael A | Out of band asset management |
US20080002894A1 (en) * | 2006-06-29 | 2008-01-03 | Winbond Electronics Corporation | Signature-based video redirection |
US8111259B1 (en) * | 2006-07-06 | 2012-02-07 | Marvell International Ltd. | Image processing apparatus having context memory controller |
US8427489B2 (en) * | 2006-08-10 | 2013-04-23 | Avocent Huntsville Corporation | Rack interface pod with intelligent platform control |
WO2008020897A2 (en) * | 2006-08-10 | 2008-02-21 | Avocent Huntsville Corporation | Rack interface pod with intelligent platform control |
US8009173B2 (en) * | 2006-08-10 | 2011-08-30 | Avocent Huntsville Corporation | Rack interface pod with intelligent platform control |
US20080040527A1 (en) * | 2006-08-14 | 2008-02-14 | Filipov Metodi N | Management module |
US7783799B1 (en) | 2006-08-31 | 2010-08-24 | American Megatrends, Inc. | Remotely controllable switch and testing methods using same |
US8120583B2 (en) * | 2006-09-08 | 2012-02-21 | Aten International Co., Ltd. | KVM switch capable of detecting keyword input and method thereof |
US20080062121A1 (en) * | 2006-09-08 | 2008-03-13 | Aten Interational Co., Ltd. | Shuttle control system for controlling kvm switch and method thereof |
US7997484B2 (en) | 2006-09-13 | 2011-08-16 | Crane Merchandising Systems, Inc. | Rich content management and display for use in remote field assets |
FR2906054B1 (en) * | 2006-09-19 | 2009-02-27 | Thales Sa | METHOD FOR RECORDING A GRAPHIC DATA STREAM, IN PARTICULAR FOR COMPUTER APLLICATIONS |
US8370479B2 (en) | 2006-10-03 | 2013-02-05 | Axeda Acquisition Corporation | System and method for dynamically grouping devices based on present device conditions |
JP4884155B2 (en) * | 2006-10-04 | 2012-02-29 | 富士通コンポーネント株式会社 | Starting device |
US7460725B2 (en) * | 2006-11-09 | 2008-12-02 | Calista Technologies, Inc. | System and method for effectively encoding and decoding electronic information |
US7970859B2 (en) * | 2006-11-09 | 2011-06-28 | Raritan Americas, Inc. | Architecture and method for remote platform control management |
US7720300B1 (en) | 2006-12-05 | 2010-05-18 | Calister Technologies | System and method for effectively performing an adaptive quantization procedure |
US20080136828A1 (en) * | 2006-12-07 | 2008-06-12 | Aten International Co., Ltd. | Remote Access Device |
US7990724B2 (en) | 2006-12-19 | 2011-08-02 | Juhasz Paul R | Mobile motherboard |
US20080155124A1 (en) * | 2006-12-20 | 2008-06-26 | Matthew Charles Compton | Apparatus, system, and method for remote multi-user kvm switching |
US8065397B2 (en) | 2006-12-26 | 2011-11-22 | Axeda Acquisition Corporation | Managing configurations of distributed devices |
KR100866603B1 (en) * | 2007-01-03 | 2008-11-03 | 삼성전자주식회사 | Data processing method and apparatus for performing deserializing and serializing |
US20080273113A1 (en) * | 2007-05-02 | 2008-11-06 | Windbond Electronics Corporation | Integrated graphics and KVM system |
US8959028B2 (en) | 2007-07-02 | 2015-02-17 | Crane Merchandising Systems, Inc. | Apparatus and method for monitoring and control of remotely located equipment |
US8478861B2 (en) | 2007-07-06 | 2013-07-02 | Axeda Acquisition Corp. | Managing distributed devices with limited connectivity |
US7774518B2 (en) | 2007-09-19 | 2010-08-10 | Aten International Co., Ltd. | Method for switching of KVM switch ports and related device |
US8477793B2 (en) * | 2007-09-26 | 2013-07-02 | Sling Media, Inc. | Media streaming device with gateway functionality |
DE102007048579B4 (en) * | 2007-10-10 | 2016-05-19 | Airbus Operations Gmbh | Multipurpose flight attendant panel |
US20090100205A1 (en) * | 2007-10-11 | 2009-04-16 | Aten International Co., Ltd. | Managment system for re-displaying characters on terminal and method thereof |
JP5372357B2 (en) * | 2007-10-18 | 2013-12-18 | 富士通コンポーネント株式会社 | KVM switch, control method therefor, multi-monitor compatible switching system, and multi-monitor compatible switching method |
US8350971B2 (en) | 2007-10-23 | 2013-01-08 | Sling Media, Inc. | Systems and methods for controlling media devices |
US8533315B2 (en) | 2007-10-25 | 2013-09-10 | Crane Merchandising Systems, Inc. | Systems and methods for monitoring performance of field assets |
US20090164675A1 (en) * | 2007-12-24 | 2009-06-25 | Aten International Co., Ltd. | Kvm switch with a remote control incorporating a memory card adapter |
US8060609B2 (en) | 2008-01-04 | 2011-11-15 | Sling Media Inc. | Systems and methods for determining attributes of media items accessed via a personal media broadcaster |
US20090177901A1 (en) * | 2008-01-08 | 2009-07-09 | Aten International Co., Ltd. | Kvm management system capable of controlling computer power |
US7769940B2 (en) * | 2008-02-13 | 2010-08-03 | Belkin International, Inc. | Switching device configured to couple a first computer to a first peripheral device and one or more second peripheral devices and method of manufacturing same |
FR2932047B1 (en) * | 2008-05-29 | 2010-08-13 | Airbus France | COMPUTER SYSTEM FOR MAINTENANCE OF A REMOTE TERMINAL AIRCRAFT |
KR101494350B1 (en) * | 2008-06-04 | 2015-02-17 | 휴렛-팩커드 디벨롭먼트 컴퍼니, 엘.피. | System and method for remote control of a computer |
US8521917B2 (en) | 2008-06-26 | 2013-08-27 | Microsoft Corporation | Remote inking |
US8667279B2 (en) | 2008-07-01 | 2014-03-04 | Sling Media, Inc. | Systems and methods for securely place shifting media content |
US20100011055A1 (en) * | 2008-07-09 | 2010-01-14 | Chih-Hua Lin | Remote desktop control system using usb cable and method thereof |
US8381310B2 (en) | 2009-08-13 | 2013-02-19 | Sling Media Pvt. Ltd. | Systems, methods, and program applications for selectively restricting the placeshifting of copy protected digital media content |
US20110221898A1 (en) * | 2008-08-21 | 2011-09-15 | The University Of Southern Queensland | Capture and playback of computer screen contents and accompanying audio |
US8667163B2 (en) * | 2008-09-08 | 2014-03-04 | Sling Media Inc. | Systems and methods for projecting images from a computer system |
US20100070925A1 (en) * | 2008-09-08 | 2010-03-18 | Sling Media Inc. | Systems and methods for selecting media content obtained from multple sources |
US9191610B2 (en) * | 2008-11-26 | 2015-11-17 | Sling Media Pvt Ltd. | Systems and methods for creating logical media streams for media storage and playback |
US20100161871A1 (en) * | 2008-12-22 | 2010-06-24 | Musa Ibrahim Kakish | Computer |
US8438602B2 (en) * | 2009-01-26 | 2013-05-07 | Sling Media Inc. | Systems and methods for linking media content |
WO2010092585A1 (en) * | 2009-02-16 | 2010-08-19 | Communitake Technologies Ltd. | A system, a method and a computer program product for automated remote control |
US8812615B2 (en) * | 2009-02-17 | 2014-08-19 | Canon Kabushiki Kaisha | Remote control of a host computer |
US8559755B2 (en) * | 2009-04-07 | 2013-10-15 | Citrix Systems, Inc. | Methods and systems for prioritizing dirty regions within an image |
US8171148B2 (en) * | 2009-04-17 | 2012-05-01 | Sling Media, Inc. | Systems and methods for establishing connections between devices communicating over a network |
JP5321253B2 (en) * | 2009-06-05 | 2013-10-23 | 船井電機株式会社 | Information display system and information display device |
US8271704B2 (en) | 2009-06-16 | 2012-09-18 | International Business Machines Corporation | Status information saving among multiple computers |
US8406431B2 (en) * | 2009-07-23 | 2013-03-26 | Sling Media Pvt. Ltd. | Adaptive gain control for digital audio samples in a media stream |
US9479737B2 (en) * | 2009-08-06 | 2016-10-25 | Echostar Technologies L.L.C. | Systems and methods for event programming via a remote media player |
US20110032986A1 (en) * | 2009-08-07 | 2011-02-10 | Sling Media Pvt Ltd | Systems and methods for automatically controlling the resolution of streaming video content |
US9565479B2 (en) * | 2009-08-10 | 2017-02-07 | Sling Media Pvt Ltd. | Methods and apparatus for seeking within a media stream using scene detection |
US8799408B2 (en) | 2009-08-10 | 2014-08-05 | Sling Media Pvt Ltd | Localization systems and methods |
US20110035466A1 (en) * | 2009-08-10 | 2011-02-10 | Sling Media Pvt Ltd | Home media aggregator system and method |
US9525838B2 (en) * | 2009-08-10 | 2016-12-20 | Sling Media Pvt. Ltd. | Systems and methods for virtual remote control of streamed media |
US8532472B2 (en) * | 2009-08-10 | 2013-09-10 | Sling Media Pvt Ltd | Methods and apparatus for fast seeking within a media stream buffer |
US8966101B2 (en) * | 2009-08-10 | 2015-02-24 | Sling Media Pvt Ltd | Systems and methods for updating firmware over a network |
US20110035765A1 (en) * | 2009-08-10 | 2011-02-10 | Sling Media Pvt Ltd | Systems and methods for providing programming content |
US8405672B2 (en) * | 2009-08-24 | 2013-03-26 | Samsung Display Co., Ltd. | Supbixel rendering suitable for updating an image with a new portion |
US9160974B2 (en) | 2009-08-26 | 2015-10-13 | Sling Media, Inc. | Systems and methods for transcoding and place shifting media content |
US8314893B2 (en) | 2009-08-28 | 2012-11-20 | Sling Media Pvt. Ltd. | Remote control and method for automatically adjusting the volume output of an audio device |
US8519960B2 (en) * | 2009-09-17 | 2013-08-27 | Aten International Co., Ltd. | Method and apparatus for switching of KVM switch ports using gestures on a touch panel |
US20110113354A1 (en) * | 2009-11-12 | 2011-05-12 | Sling Media Pvt Ltd | Always-on-top media player launched from a web browser |
US9015225B2 (en) | 2009-11-16 | 2015-04-21 | Echostar Technologies L.L.C. | Systems and methods for delivering messages over a network |
US8799485B2 (en) * | 2009-12-18 | 2014-08-05 | Sling Media, Inc. | Methods and apparatus for establishing network connections using an inter-mediating device |
US8626879B2 (en) | 2009-12-22 | 2014-01-07 | Sling Media, Inc. | Systems and methods for establishing network connections using local mediation services |
US9178923B2 (en) * | 2009-12-23 | 2015-11-03 | Echostar Technologies L.L.C. | Systems and methods for remotely controlling a media server via a network |
US9275054B2 (en) | 2009-12-28 | 2016-03-01 | Sling Media, Inc. | Systems and methods for searching media content |
US8856349B2 (en) | 2010-02-05 | 2014-10-07 | Sling Media Inc. | Connection priority services for data communication between two devices |
US9183560B2 (en) | 2010-05-28 | 2015-11-10 | Daniel H. Abelow | Reality alternate |
TWI480731B (en) * | 2010-06-30 | 2015-04-11 | Insyde Software Corp | Adapter and debug method using the same |
US8671153B1 (en) | 2010-08-20 | 2014-03-11 | Acqis Llc | Low cost, high performance and high data throughput server blade |
US20120260013A1 (en) * | 2011-04-06 | 2012-10-11 | Oct Technology Co.,Ltd. | KVM switcher (Multi-computer switcher) with integrated parallel transmission, serial peripheral interface and universal serial bus |
US8615159B2 (en) | 2011-09-20 | 2013-12-24 | Citrix Systems, Inc. | Methods and systems for cataloging text in a recorded session |
US8825931B2 (en) * | 2011-11-04 | 2014-09-02 | International Business Machines Corporation | KVM switch system capable of wirelessly transmitting keyboard-mouse-data between wired input/output devices based on a security clearance level |
TWI484376B (en) * | 2012-08-09 | 2015-05-11 | Pixart Imaging Inc | Interacting system and remote controller |
WO2014066281A1 (en) * | 2012-10-23 | 2014-05-01 | Avocent Huntsville Corp. | SYSTEM AND METHOD FOR ACCESSING DISK IMAGE FILES USING HTML5 KVM/vMEDIA CLIENT RUNNING IN A WEB BROWSER |
US9313602B2 (en) | 2012-10-24 | 2016-04-12 | Beta Brain, Inc. | Remotely accessing a computer system |
US9274742B2 (en) | 2012-10-25 | 2016-03-01 | PixiOnCloud, Inc. | Visual-symbolic control of remote devices having display-based user interfaces |
US10445270B2 (en) * | 2017-06-09 | 2019-10-15 | Qualcomm Incorporated | Configuring optimal bus turnaround cycles for master-driven serial buses |
TWI765211B (en) * | 2020-01-08 | 2022-05-21 | 威眾企業股份有限公司 | hub switch |
Family Cites Families (117)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5742677A (en) | 1995-04-03 | 1998-04-21 | Scientific-Atlanta, Inc. | Information terminal having reconfigurable memory |
US3634830A (en) | 1969-06-13 | 1972-01-11 | Ibm | Modular computer sharing system with intercomputer communication control apparatus |
US3955188A (en) | 1971-01-04 | 1976-05-04 | Honeywell Information Systems Inc. | Encoding technique for enabling a device to process different types of digital information transmitted along a single information channel |
US3774158A (en) | 1972-01-06 | 1973-11-20 | Rca Corp | Multiple terminal display system |
US4081797A (en) | 1972-11-03 | 1978-03-28 | Heath Company | On-screen channel display |
US4150429A (en) | 1974-09-23 | 1979-04-17 | Atex, Incorporated | Text editing and display system having a multiplexer circuit interconnecting plural visual displays |
US4078249A (en) | 1976-06-01 | 1978-03-07 | Raytheon Company | Digital display composition system |
US4243984A (en) | 1979-03-08 | 1981-01-06 | Texas Instruments Incorporated | Video display processor |
US4313176A (en) | 1980-03-07 | 1982-01-26 | The Lockwood Association, Inc. | Data controlled switch for telephone inputs to a computer |
US4479122A (en) | 1982-03-05 | 1984-10-23 | At&T Bell Laboratories | Remotely controlled switched access to the console port of an electronic computer |
US4599611A (en) | 1982-06-02 | 1986-07-08 | Digital Equipment Corporation | Interactive computer-based information display system |
JPS59114631A (en) | 1982-12-22 | 1984-07-02 | Hitachi Ltd | Terminal control device |
US4641262A (en) | 1983-03-07 | 1987-02-03 | International Business Machines Corporation | Personal computer attachment for host system display station |
US4665501A (en) | 1983-09-30 | 1987-05-12 | Esprit Systems, Inc. | Workstation for local and remote data processing |
US4823256A (en) | 1984-06-22 | 1989-04-18 | American Telephone And Telegraph Company, At&T Bell Laboratories | Reconfigurable dual processor system |
EP0174099B1 (en) | 1984-08-06 | 1993-07-14 | Texas Instruments Incorporated | Fiber optic terminal interface |
US4630284A (en) | 1984-12-28 | 1986-12-16 | Gte Laboratories Incorporated | Low power line driving digital transmission system |
US4680622A (en) | 1985-02-11 | 1987-07-14 | Ncr Corporation | Apparatus and method for mixing video signals for simultaneous presentation |
US4710917A (en) | 1985-04-08 | 1987-12-01 | Datapoint Corporation | Video conferencing network |
US4939507A (en) | 1986-04-28 | 1990-07-03 | Xerox Corporation | Virtual and emulated objects for use in the user interface of a display screen of a display processor |
US4807184A (en) | 1986-08-11 | 1989-02-21 | Ltv Aerospace | Modular multiple processor architecture using distributed cross-point switch |
SE454730B (en) | 1986-09-19 | 1988-05-24 | Asea Ab | PROCEDURE AND COMPUTER EQUIPMENT FOR SHORT-FREE REPLACEMENT OF THE ACTIVITY FROM ACTIVE DEVICES TO EMERGENCY UNITS IN A CENTRAL UNIT |
US5230066A (en) | 1986-09-19 | 1993-07-20 | Mitsubishi Denki Kabushiki Kaisha | Microcomputer |
US5029111A (en) | 1987-04-29 | 1991-07-02 | Prime Computer, Inc. | Shared bit-plane display system |
US4768083A (en) | 1987-04-29 | 1988-08-30 | Rca Licensing Corporation | Digital TV having on-screen display feature |
US5268676A (en) | 1987-09-11 | 1993-12-07 | Cybex Corporation | Computer-monitor extended range communications link |
US5465105A (en) | 1987-09-11 | 1995-11-07 | Cybex Corporation | Autosensing switching system |
US4907079A (en) | 1987-09-28 | 1990-03-06 | Teleview Rating Corporation, Inc. | System for monitoring and control of home entertainment electronic devices |
GB8724789D0 (en) * | 1987-10-19 | 1987-11-25 | British Telecomm | Signal coding |
US5121486A (en) | 1987-11-20 | 1992-06-09 | Hitachi, Ltd | Network control system for dynamically switching a logical connection between an identified terminal device and an indicated processing unit |
US4879716A (en) | 1987-12-23 | 1989-11-07 | Bull Hn Information Systems Inc. | Resilient data communications system |
US4800429A (en) | 1988-03-14 | 1989-01-24 | Motorola, Inc. | Auto sync polarity control circuit for use with monitor |
US5043866A (en) | 1988-04-08 | 1991-08-27 | International Business Machines Corporation | Soft checkpointing system using log sequence numbers derived from stored data pages and log records for database recovery |
US5280583A (en) | 1988-05-13 | 1994-01-18 | Hitachi, Ltd. | System and method for performing interlocution at a plurality of terminals connected to communication network |
US4949248A (en) | 1988-07-15 | 1990-08-14 | Caro Marshall A | System for shared remote access of multiple application programs executing in one or more computers |
US5222212A (en) | 1988-09-16 | 1993-06-22 | Chips And Technologies, Inc. | Fakeout method and circuitry for displays |
JPH0290335A (en) | 1988-09-28 | 1990-03-29 | Hitachi Ltd | Remote operation control system for computer system |
US5036484A (en) | 1988-11-23 | 1991-07-30 | International Business Machines Corporation | Personal computer/host emulation system for handling host data with personal computer application programs at personal computers |
US4953159A (en) | 1989-01-03 | 1990-08-28 | American Telephone And Telegraph Company | Audiographics conferencing arrangement |
US4953027A (en) | 1989-04-24 | 1990-08-28 | Motorola Inc. | OSD in a TV receiver including a window, smoothing and edge enhancing |
US5117225A (en) | 1989-05-01 | 1992-05-26 | Summit Micro Design | Computer display screen monitoring system |
US5214785A (en) | 1989-09-27 | 1993-05-25 | Third Point Systems, Inc. | Controller with keyboard emulation capability for control of host computer operation |
US5099319A (en) | 1989-10-23 | 1992-03-24 | Esch Arthur G | Video information delivery method and apparatus |
US4949169A (en) | 1989-10-27 | 1990-08-14 | International Business Machines Corporation | Audio-video data interface for a high speed communication link in a video-graphics display window environment |
JPH03160494A (en) | 1989-11-10 | 1991-07-10 | Internatl Business Mach Corp <Ibm> | Datacprocessing device |
US5051720A (en) | 1989-11-13 | 1991-09-24 | Secure Telecom, Inc. | Remote control system using power line of remote site |
US5128766A (en) | 1989-11-30 | 1992-07-07 | Goldstar Co., Ltd. | Multiple television receiver with teletext function |
US5333286A (en) | 1989-12-13 | 1994-07-26 | Joseph Weinberger | Two way copier monitoring system |
JP2793308B2 (en) | 1989-12-21 | 1998-09-03 | 株式会社日立製作所 | Dialogue system |
US5161156A (en) | 1990-02-02 | 1992-11-03 | International Business Machines Corporation | Multiprocessing packet switching connection system having provision for error correction and recovery |
JP3092135B2 (en) | 1990-03-13 | 2000-09-25 | 株式会社日立製作所 | Application execution control method |
US5260778A (en) | 1990-06-26 | 1993-11-09 | General Instrument Corporation | Apparatus for selective distribution of messages over a communications network |
US5220380A (en) | 1990-08-10 | 1993-06-15 | Minolta Camera Kabushiki Kaisha | Control system for copying machines with improved communication function for centralized control unit |
US5349675A (en) | 1990-09-04 | 1994-09-20 | International Business Machines Corporation | System for directly displaying remote screen information and providing simulated keyboard input by exchanging high level commands |
US5327156A (en) | 1990-11-09 | 1994-07-05 | Fuji Photo Film Co., Ltd. | Apparatus for processing signals representative of a computer graphics image and a real image including storing processed signals back into internal memory |
US5261079A (en) | 1990-12-18 | 1993-11-09 | International Business Machines Corporation | Interface for keyboard emulation provided by an operating system |
US5617547A (en) | 1991-03-29 | 1997-04-01 | International Business Machines Corporation | Switch network extension of bus architecture |
US5611038A (en) * | 1991-04-17 | 1997-03-11 | Shaw; Venson M. | Audio/video transceiver provided with a device for reconfiguration of incompatibly received or transmitted video and audio information |
JPH0546568A (en) | 1991-08-08 | 1993-02-26 | Internatl Business Mach Corp <Ibm> | Dispersion application execution device and method |
EP0532102B1 (en) | 1991-09-11 | 1998-04-22 | Lucent Technologies Inc. | System for controlling data access to a data apparatus |
JPH0589069A (en) | 1991-09-30 | 1993-04-09 | Toshiba Corp | Dispersion type control system |
FR2682786B1 (en) | 1991-10-17 | 1993-12-10 | Bull Sa | DOWNLOADING AN OPERATING SYSTEM THROUGH A NETWORK. |
US5287461A (en) | 1991-10-31 | 1994-02-15 | Sun Microsystems, Inc. | Method and apparatus for remotely accessing a plurality of server consoles |
US5689671A (en) | 1991-11-27 | 1997-11-18 | Icl Systems Ab | System for reducing quantity of data transmitted to a user unit by transmitting only an identifier which points to pre-stored information in the user unit |
US5301028A (en) | 1991-11-29 | 1994-04-05 | Scientific-Atlanta, Inc. | Method and apparatus for displaying channel identification information |
US5477262A (en) | 1991-11-29 | 1995-12-19 | Scientific-Altanta, Inc. | Method and apparatus for providing an on-screen user interface for a subscription television terminal |
US5247364A (en) | 1991-11-29 | 1993-09-21 | Scientific-Atlanta, Inc. | Method and apparatus for tuning data channels in a subscription television system having in-band data transmissions |
US5317391A (en) | 1991-11-29 | 1994-05-31 | Scientific-Atlanta, Inc. | Method and apparatus for providing message information to subscribers in a cable television system |
US5486869A (en) | 1992-02-18 | 1996-01-23 | Cooper; J. Carl | Synchronizing signal separating apparatus and method |
US5526024A (en) | 1992-03-12 | 1996-06-11 | At&T Corp. | Apparatus for synchronization and display of plurality of digital video data streams |
US5483634A (en) * | 1992-05-19 | 1996-01-09 | Canon Kabushiki Kaisha | Display control apparatus and method utilizing first and second image planes |
US5392400A (en) | 1992-07-02 | 1995-02-21 | International Business Machines Corporation | Collaborative computing system using pseudo server process to allow input from different server processes individually and sequence number map for maintaining received data sequence |
US5732212A (en) | 1992-10-23 | 1998-03-24 | Fox Network Systems, Inc. | System and method for remote monitoring and operation of personal computers |
US5566339A (en) | 1992-10-23 | 1996-10-15 | Fox Network Systems, Inc. | System and method for monitoring computer environment and operation |
US5592551A (en) | 1992-12-01 | 1997-01-07 | Scientific-Atlanta, Inc. | Method and apparatus for providing interactive electronic programming guide |
US5657414A (en) | 1992-12-01 | 1997-08-12 | Scientific-Atlanta, Inc. | Auxiliary device control for a subscriber terminal |
US5367571A (en) | 1992-12-02 | 1994-11-22 | Scientific-Atlanta, Inc. | Subscriber terminal with plug in expansion card |
US5357276A (en) | 1992-12-01 | 1994-10-18 | Scientific-Atlanta, Inc. | Method of providing video on demand with VCR like functions |
US5715515A (en) | 1992-12-02 | 1998-02-03 | Scientific-Atlanta, Inc. | Method and apparatus for downloading on-screen graphics and captions to a television terminal |
US5440632A (en) | 1992-12-02 | 1995-08-08 | Scientific-Atlanta, Inc. | Reprogrammable subscriber terminal |
MX9401216A (en) | 1993-02-16 | 1994-08-31 | Scientific Atlanta | SYSTEM AND METHOD FOR REMOTELY SELECTING SUBSCRIBERS, AND FOR CONTROLLING MESSAGES TO SUBSCRIBERS ON A CABLE TELEVISION SYSTEM. |
US5381477A (en) | 1993-02-16 | 1995-01-10 | Scientific-Atlanta, Inc. | Method of selecting cable television converter groups |
US5608872A (en) | 1993-03-19 | 1997-03-04 | Ncr Corporation | System for allowing all remote computers to perform annotation on an image and replicating the annotated image on the respective displays of other comuters |
US5499377A (en) | 1993-05-03 | 1996-03-12 | Designed Enclosures, Inc. | Multi-computer access switching system |
JP3260910B2 (en) * | 1993-05-19 | 2002-02-25 | 株式会社リコー | Encoding method |
US5768224A (en) | 1993-05-28 | 1998-06-16 | Sony Corporation | AV system and method of establishing a connection setting for AV component devices |
US5485221A (en) | 1993-06-07 | 1996-01-16 | Scientific-Atlanta, Inc. | Subscription television system and terminal for enabling simultaneous display of multiple services |
BR9406793A (en) | 1993-06-07 | 1996-01-30 | Scientific Atlanta | Subscriber terminal display system for pay-TV system display system to generate a first video signal and process in display system to generate a first video signal |
JPH0746579A (en) | 1993-07-21 | 1995-02-14 | Sony Corp | Signal monitoring device |
US5448697A (en) | 1993-09-10 | 1995-09-05 | Dell Usa, L.P. | Method and apparatus for simplified control of a video monitor |
US5583562A (en) | 1993-12-03 | 1996-12-10 | Scientific-Atlanta, Inc. | System and method for transmitting a plurality of digital services including imaging services |
US5606604A (en) | 1993-12-13 | 1997-02-25 | Lucent Technologies Inc. | System and method for preventing fraud upon PBX through a remote maintenance or administration port |
GB9400101D0 (en) | 1994-01-05 | 1994-03-02 | Thomson Consumer Electronics | Consumer interface for a satellite television system |
US5583993A (en) | 1994-01-31 | 1996-12-10 | Apple Computer, Inc. | Method and apparatus for synchronously sharing data among computer |
US5539822A (en) | 1994-04-19 | 1996-07-23 | Scientific-Atlanta, Inc. | System and method for subscriber interactivity in a television system |
US5534942A (en) | 1994-06-17 | 1996-07-09 | Thomson Consumer Electronics, Inc. | On screen display arrangement for digital video signal processing system |
US5489947A (en) | 1994-06-17 | 1996-02-06 | Thomson Consumer Electronics, Inc. | On screen display arrangement for a digital video signal processing system |
US5541666A (en) | 1994-07-06 | 1996-07-30 | General Instrument | Method and apparatus for overlaying digitally generated graphics over an analog video signal |
JP3534331B2 (en) | 1994-08-09 | 2004-06-07 | ゼロックス コーポレイション | How to build multi-segment print jobs from a variety of local and remote sources using a network interface |
US5802213A (en) * | 1994-10-18 | 1998-09-01 | Intel Corporation | Encoding video signals using local quantization levels |
US5552832A (en) * | 1994-10-26 | 1996-09-03 | Intel Corporation | Run-length encoding sequence for video signals |
US5701161A (en) | 1994-12-14 | 1997-12-23 | Williams; Mark C. | Method and apparatus for providing real time data on a viewing screen concurrently with any programing in process |
US5774859A (en) | 1995-01-03 | 1998-06-30 | Scientific-Atlanta, Inc. | Information system having a speech interface |
US5581303A (en) | 1995-01-18 | 1996-12-03 | Radius Inc. | Video timing signal generation circuit |
US5604509A (en) | 1995-04-14 | 1997-02-18 | Advent Design, Inc. | Remote display monitor system |
US5674003A (en) | 1995-04-28 | 1997-10-07 | Andersen; David B. | Mechanisms for accessing unique features of telephony networks from a protocol-Independent data transport interface |
US5708961A (en) | 1995-05-01 | 1998-01-13 | Bell Atlantic Network Services, Inc. | Wireless on-premises video distribution using digital multiplexing |
US5486868A (en) | 1995-05-19 | 1996-01-23 | Winbond Electronics Corporation | Generator for scan timing of multiple industrial standards |
US5721842A (en) | 1995-08-25 | 1998-02-24 | Apex Pc Solutions, Inc. | Interconnection system for viewing and controlling remotely connected computers with on-screen video overlay for controlling of the interconnection switch |
US5757424A (en) * | 1995-12-19 | 1998-05-26 | Xerox Corporation | High-resolution video conferencing system |
US5719622A (en) | 1996-02-23 | 1998-02-17 | The Regents Of The University Of Michigan | Visual control selection of remote mechanisms |
US6571016B1 (en) * | 1997-05-05 | 2003-05-27 | Microsoft Corporation | Intra compression of pixel blocks using predicted mean |
US6173082B1 (en) * | 1997-03-28 | 2001-01-09 | Canon Kabushiki Kaisha | Image processing apparatus and method for performing image processes according to image change and storing medium storing therein image processing programs |
US6304895B1 (en) * | 1997-08-22 | 2001-10-16 | Apex Inc. | Method and system for intelligently controlling a remotely located computer |
WO1999010801A1 (en) * | 1997-08-22 | 1999-03-04 | Apex Inc. | Remote computer control system |
US6138164A (en) * | 1997-11-14 | 2000-10-24 | E-Parcel, Llc | System for minimizing screen refresh time using selectable compression speeds |
US6016166A (en) * | 1998-08-31 | 2000-01-18 | Lucent Technologies Inc. | Method and apparatus for adaptive synchronization of digital video and audio playback in a multimedia playback system |
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EP1214659A1 (en) | 2002-06-19 |
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