CA2214515A1 - Methods and apparatus for protecting the integrity of process data stored on a removable storage medium - Google Patents
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- CA2214515A1 CA2214515A1 CA002214515A CA2214515A CA2214515A1 CA 2214515 A1 CA2214515 A1 CA 2214515A1 CA 002214515 A CA002214515 A CA 002214515A CA 2214515 A CA2214515 A CA 2214515A CA 2214515 A1 CA2214515 A1 CA 2214515A1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F11/00—Error detection; Error correction; Monitoring
- G06F11/07—Responding to the occurrence of a fault, e.g. fault tolerance
- G06F11/14—Error detection or correction of the data by redundancy in operation
- G06F11/1402—Saving, restoring, recovering or retrying
- G06F11/1415—Saving, restoring, recovering or retrying at system level
- G06F11/1435—Saving, restoring, recovering or retrying at system level using file system or storage system metadata
Abstract
Methods and apparatus for preventing the loss and/or corruption of process data stored by data collection and/or test instruments (referred to hereinafter collectively as "recording instruments"), which may otherwise result from events such as the removal of aforementioned storage media while data transfer operations are in progress; loss of power to the recording instrument while data transfer operations are in progress; and/or the execution of internal CPU traps or other CPU reset conditions while data transfer operations are in progress. The methods and apparatus contemplated by the invention also provide for the recovery of process data which has been corrupted during a power loss or CPU reset when normal operation of a recording instrument resumes.
Description
WO 96/34336 PCT/U~ ~Ci'~'~76 METHODS AND APPARATUS FOR PROTECTING THE INTE;GRITY
OF PROCESS DATA Sl[ ORED ON A REMOVABLE STORAGE MEDIUM
RACKGROUNT~ OF THF ~VF~TION
1. Field of the Inv~ntion s The invention relates generally to methods and a~p~dlus used for protecting the integrity of process data stored on removable storage media such as floppy disks, PCMCLA memory cards, etc.
More particularly, the invention relates to methods and a~aLLls for preventing the loss and/or Cu~ lion of process data stored by data collection and/or 0 test instruments (rercll~d to he,-marL~l collectively as "recording i.~ll~lllle~ "), which may otherwise result from events such as the removal of aforenn~ntioned storage media while data transfer operations are in progress; loss of power to the recording instrument while data transfer operations are in progress; and/or the execution of int~rn~lCPU traps or other CPU reset conditions while data transfer operations are in progress.
Furthermore, the methods and a~udlus co,ltt;.ll~lated by the invention provide for the recovery of process data which has been corrupted during a power loss or CPU reset when normal operation of a recording instrument resllmes.
OF PROCESS DATA Sl[ ORED ON A REMOVABLE STORAGE MEDIUM
RACKGROUNT~ OF THF ~VF~TION
1. Field of the Inv~ntion s The invention relates generally to methods and a~p~dlus used for protecting the integrity of process data stored on removable storage media such as floppy disks, PCMCLA memory cards, etc.
More particularly, the invention relates to methods and a~aLLls for preventing the loss and/or Cu~ lion of process data stored by data collection and/or 0 test instruments (rercll~d to he,-marL~l collectively as "recording i.~ll~lllle~ "), which may otherwise result from events such as the removal of aforenn~ntioned storage media while data transfer operations are in progress; loss of power to the recording instrument while data transfer operations are in progress; and/or the execution of int~rn~lCPU traps or other CPU reset conditions while data transfer operations are in progress.
Furthermore, the methods and a~udlus co,ltt;.ll~lated by the invention provide for the recovery of process data which has been corrupted during a power loss or CPU reset when normal operation of a recording instrument resllmes.
2. nescription of the Rel~tt?~l Art Methods and a~p~dL~ls for protecting the integrity of data stored on removable storage media are known in the prior art. For example, it is known that by using an Ullh~ Lible Power Supply (UPS), loss of data being ll~ulsrt;ll~;d (again, by way of example) from storage in a computer to a removable floppy disk inserted into the computer, can be prevented should a power outage occur during the data ~ s~
process.
When the nature of a given recol~lillg instrument and the recording environrnent permits, assuring data integrity on removable storage media (and recognizing that a problem may exist), can be as simple as an on site operator observing that a power failure has occurred or that a plug has been removed from a wall socket;
observing that a warning appears on a colll~uLe~ display screen should, for example, a floppy disk be removed prior to an in progress data transfer being completed; or using hardware and software solutions, such as the aforementioned UPS andlor software for CA 02214~1~ 1997-09-03 WO 96/34336 PCT/U~''rr~76 providing the aforementioned on screen warnings to an operator, etc., to recognize potential problems and protect data integrity.
The problems associated with ~sl~ring data integrity for data stored on removable storage media in opeldlor ~ttentle~l mainframe or PC coll.~u~hlg s environment~, and even for process data recording envh~ol.l.lell~ in which an operator ~elrolllls "one-shot" utility type lecordillg and is physically present to observe and control the data recording process; differ considerably from the problems experienced when trying to assure the inleg-ily of process data being recorded on removable storage media by often lm~tt~n~le~l, field located, "stand alone" recording instruments (defined herein as instruments not requiring full time o~e.dlol supervision or interaction to actually perform the data recording function), which is the type of recording instr -ment~tion in which the present invention finds utility.
In the aforementioned environment in which the invention finds utility, the removable storage media rather than being used in the previously mentioned "one l s shot" utility type recordillg context, is typically used as a continuous storage medium.
Furthermore, in the aforementioned environment in which the invention finds utility, UPSs are normally unavailable or too costly to provide data integrity protection; and operators do not normally attend the recording device over the whole continuous recording period which can run for days, weeks and even longer periods of time.
In view of the above, in the context in which the present invention finds utility, the problem of ~nring the integrity of data recorded on the continuous medium is compounded by the fact that the safeguards of either being under assured continuous power and/or direct operator supervision, are not necess~rily present.
Accordingly, it would be desirable to provide methods and d~ lldLLIS for 2s assuring the integrity of process data stored on a removable storage media associated with stand alone data recording instruments being used to continuously record process data.
Furthermore, it would be desirable to provide methods and apparatus for ~sllrin~ the integrity of process data stored on a removable storage media in a manner that does not require the use of an e~t~rn~l power source, such as an Uninterruptible Power Supply (UPS).
-CA 02214~1~ 1997-09-03 3 ~ ;', Still further, it would be desirable to provide methods and apparatus for assuring the integrity of process data stored on a removable storage media in a manner that does not require the full time presence of an operator to manage and observe the data recording process per se.
s Further yet, it would be desirable to provide methods and apparatuswhich enable process data which has been corrupted during a power loss or CPU reset, to be recovered when norrnal operation of a recording instrument resumes.
SUMM~RY OF THF. INVFNTION
The present invention provides a method as defined in Claim I
o hereinafter.
The present invention also provides a method as defined in Claim 23 hereinafter. The present invention also provides apparatus as defined in Claim 24 hereinafter.
The present invention may provide any one or more of the features of dependent Claims 2 to 22 or Claims 25 and 26 hereinafter.
Thus, the invention may provide methods and apparatus for assuring the integrity of process data stored on a removable storage media associated with stand alone data recording instruments being used to continuously record process data.Furthermore, the invention may provide methods and apparatus for assuring the integrity of process data stored on a removable storage media in a manner that does not require the use of an external power source, such as an Uninterruptible Power Supply (UPS).
Still further, the invention may provide methods and apparatus for assuring the integrity of process data stored on a removable storage media in a manner 2s that does not require the full time presence of an operator to manage and observe the data recording process per se.
Further yet, the invention may provide methods and apparatus which enable process data which has been corrupted during a power loss or CPU reset, to be recovered when normal operation of a recording instrument resumes.
The information on the removable medium may be protected against two basic causes of lost data: corruption of the file control structures for the medium, and corruption of the data control structures within a file.
~MEl~lDED SHET
CA 02214~1~ 1997-09-03 Most file creation and management utilities, such as DOS, IJNIX, etc., do not provide any inherent mechanism for assuring the integrity of file controlstructures transferred to a removable storage medium. However, according to one aspect of the invention, the file control structures can be protected by allocating file 5 space on the medium during a one-time initialization procedure. Furthermore, according to the invention, no storage of process data is permitted until initialization has been successfully completed. The instrument will continue to accumulate process data in an internal memory (e.g., internal random access memory (RAM)), while initialization is taking place.
BR~EF DESCRIPTION OF THF DRAWrNG
FIG. 1 depicts an exemplary programmable process data recording instrument of the type contemplated by one aspect of the invention for use in conjunction with a removable floppy disk.
FIG. 2 depicts a further exemplary programmable process data recording 15 instrument of the type contemplated by the invention for use in conjunction with a removable PCMCIA memory card.
FIG. 3 depicts an overview of the data integrity protection process contemplated by a preferred embodiment of the present invention.
FIG. 4 depicts, in accordance with the teachings of one embodiment of 20 the invention, an exemplary logical layout for a DOS created set of disk (or memory card) file control structures.
FIG. S depicts, in accordance with the teachings of one embodiment of the invention, an exemplary logical layout for each of the data files depicted in FIG. 4.
DF~~~ S~ ~r-~
CA 02214~1~ 1997-09-03 FIG. 6 depicts, in accordance with the te~t~hinge of one embodiment of the invention, an exemplary logical layout for each data block depicted in FIG. 5.
FIG. 7 depicts, in accordance with the te~rhin~e of one embodiment of the invention, an illustrative set of process steps for form~ltinP the storage m~ m .
FIG. 8 depicts, in acco~ ce with the te~rhinge of one embodiment of c the invention, an illustrative set of process steps for configuring non-volatile memory with a set of storage operation p~r~m~t~rS.
FIG. 9 depicts, in accordance with the te~rhin~s of one embodiment of the invention, an illustrative set of process steps for initi~li7.ing the storage medium.
0 FIG. 10A and FIG. 10B depict, in accordance with the te~chinge of one embodiment of the invention, an illustrative set of process steps for m~n~ging the data transfer process co~ lated by the invention.
FIG. 11 depicts7 in accordance with the te~rhing~ of one embodiment of the invention, an illustrative set of process steps for recovering from a power loss condition.
FIG. 12 depicts, in accordance with the tto~rllingc of one embodiment of the invention, an illustrative set of process steps for recovering from a RAM loss condition.
nF,TATT,F,n nF,SCRllPTION
Prior to describing the details of the a~ lldtUS and process steps contempl~ted by the invention, certain assumptions and definitions which have been made for the sake of illustration and convenience in providing this detailed description will be explained.
The term "disk" is used herein as a generic reference to the aforementioned removable storage medium. Those skilled in the art will readily appreciate that the processes set forth herein will work for any properly formsltted devices (where the DOS format is used for the sake of illustration herein), including floppy disks (of any density), PCMCIA memory cards, etc.
As indicated hereinabove, the invention is presented, for the sake of illustration only, ~eel-ming that DOS is the file creation and management utility used for pro~ ly form~t~ing the storage medium. Those skilled in the art will readily appreciate that other commercially available and/or user developed file creation and management -CA 02214~1~ 1997-09-03 _g _ utilities (e.g., I~NIX, etc.), may be used to practice the invention after making a~ l.ate modifications to take into account the utility dependent file control structures associated with a given utility.
Furthermore, the invention is set forth in the context of a stand alone 5 lCCOldillg i~ ent (to be described in detail hc.~inar~r with reference to FIG. 1 and FIG. 2), assumed to include random access memory (RAM) within which process is d for data transfer to tlhe removable metlillm and stored, at least te~ ol~;ly, prior to l~ r~r to the medium.
According to the invention, the RAM is preferably backed (for example, 10 a capacitor backed RAM), to insure that if P~tPrn~l power to the instrument is interrupted the ~AM contents will be m~int~in~l for (in the exemplary capacitor backed RAM in~t~n~e) the discharge life of the capacitor (e.g., ~loxill~alcly 90 minllte~ in one embodiment of the invention). Again, it is not nrce~ry for the RAM included in the recording h.sL.~unent in which the invention is practiced to be backed; but it is 15 preferable to increase the units ability to protect the illlegl;ly of process data being stored prior to succes~ful transfer; and for providing a process data back up after data is transferred.
Finally, the stand alone recording instruments in which the invention may be practiced are assumed to be "progr~mm~ble" devices; that is, devices that are 20 provided with access to (and execute) programs which implement the various processes described herein to protect the integrity of the data being recorded on the removable storage media.
Specific examples of commercially available stand alone lccolding devices of the type cont~rnplated by the invention (used to record process data) are 2s microprocessor based video recorders and controllers available from Leeds & Northrup Company.
Those skilled in the art will readily be able to implement the processes described herein in the form of programs suitable for execution by a microprocessor, ~C~sllming a knowledge of the file creation and management utility being employed 30 (such as the exemplary DOS utility) and having the benefit of the various flow charts depicted in the Drawing.
CA 02214~1~ 1997-09-03 WO 9f '31~36 PCI~/US96/05676 Reference should now be made to FIG. 1 which, as indicated hereinbefore, depicts an exemplary programmable process data recordillg instrument of the type contemplated by one aspect of the invention for use in conjunction with a removable floppy disk.
s In particular, exemplary programmable process data l~cul~dillg instrument 100 shown in FIG. 1 depicts the device as inl~hl-ling: pro r~Tnm~ble data procç~ing means 101 shown, by way of example, as a microprocessor; Input/Output (I/O) means 102, coupled to programmable data processing means 101 via link 150, for leceivhlg raw process data input to said instrument via exemplary wiring connections l S 1 (where 0 I/O means 102 as depicted in FIG. 1 may be any one of a number of well known circuit devices for me~ ring process data input); memory means 103, coupled to programmable data proces.cing means 101 via link 152, for at least temporarily storing raw process data (received over links 150, l S l and 152), and/or process data derived by the instrument itself (derived via programmable data proces~ing device 101);
15 non-volatile memory means 104, shown coupled to the programmable data processing means via link 153, for storing a set of configuration parameters used to configure the removable media; media interface means 105, shown coupled to programmable data proces~ing means 101 via link 154, for receiving the removable storage medium when properly inserted therein and making the storage medium available to programmable 20 data proces~ing means 101 for data transfer operations; and means for generating a signal, 106, to programmable data processing means 101 whenever the removable media is not properly inserted in media int~ ce means 105, to thereby enable programmable data processing means 101 to recognize a condition in which data transfer operations between memory means 102 and the removable storage medium is to 25 be inhibited.
An example of the aforementioned "means for generating a signal"
(reference numeral 106), is depicted in FIG 1 as a micro-switch arrangement (a switch 1 06a and switch activator 1 06b), for generating a software detectable signal (detectable by software running on programmable data processing device 101), whenever front door 30 107 of the instrument (through which the removable media is installed and removed) has been opened.
-CA 02214~ i 1997-09-03 WO 9r'31~76 r~ /0S676 As intlic~ted hereinbefore, in accordance with one aspect of the invention, upon detection of a "door open" condition (i.e., whenever switch activator 106b is not c~ in~ switch 106a to be activated), software contemplated by the preferred embodiment of the invention (running on programmable data proces~in~ device 101 ) 5 will immc~ tely stop any further transfer of data to or from the removable storage medium. This action p~ lL~ the potential loss of data due to manual removal of the storage m~ lm while data transfer is taking place. Data storage, according to the t~ in~s of the invention, will not resume until door 107 has been closed.
It should be noted that if door 107 is opened during a disk data transfer, 0 the software will complete the llansfer and then inhibit any further disk activity. The latency in the depicted exemplary system is approximately 100 milliceconds, which will allow the software to safely complete an active data transfer prior to ejection of the disk.
According to a ~l~rell~d embodiment of the invention, in~llumGlll 100 will continue to A~ccllm~ te process data in internal memory 103 while a data transfer 5 initi~li7~tion process (to be explained hereinafter) takes place.
Furthermore, according to a ~lc;r~ ed embodiment of the invention, the information in exemplary RAM memory 103 may be m~intslin~ should a power failureoccur through the use of a capacitor-discharge battery device, such as device 120 depicted in FIG. 1.
Finally, it should be noted that according to a ~lc;rell~d embodiment of the invention, although not depicted in the Drawing, software programs implementing the processes taught hereinafter are embedded in a read only memory (ROM) accessible to programmable data processing device 101. It should be further noted that the 25 invention is not inten(le~l to be limited to this preferred (ROM) program storage me-~h~ni~m Reference should now be made to FIG. 2 which, as indicated hereinbefore, depicts a further exemplary progr~mm~ble process data recording - instrument of the type contemplated by the invention for use in conjunction with a 30 removable PCMCIA memory card.
In particular, FIG. 2 is identical to FIG. 1, with the exception that a PCMCIA card interface, 201, is shown within recording instrument 200.
CA 022l4~l~ l997-09-03 Reference should now be made to FIG. 3 which, as indicated hereinbefore, depicts an overview of the data integrity protection process contemplated by a pLerell~d embodiment of the present invention.
The illustrative process depicted in FIG. 3 is shown to include steps 5 directed to addressing three major considerations: (1 ) pr~dlion of the removable storage medium and int~rn~l instrument storage facility (e.g., RAM), to support data integrity plole~;lion; (2) m~n~ging the data ~ ,r.. process per se to achieve the desired data integrity protection; and (3) leco~,cl~ operations (with some recovery fe~Lules being optional, as will be explained hel~ &rl~ following a power loss condition and/or a lo RAM loss condition (e.g., where RAM fails due to a power outage, expiration of a battery backed power window, etc.).
More particularly, the process overview depicted in FIG. 3, for that portion of the process dealing with the pr~ alion of the removable storage medium and intern~l instrument storage facility to support data integrity protection, includes 1S steps of: form~tting the removable storage m~ lm (shown at block 301); configuring the storage parameters (shown at block 302); and initi~li7in~ the storage system (shown at block 303).
Each of aforementioned steps (shown at blocks 301, 302 and 303) will be exrl~ine~l in greater detail hereinafter with reference to FIG. 7, FIG. 8 and FIG. 9, respectively.
The FIG. 3 overview goes on to depict the step of m~n~ging the data transfer process per se (to achieve the desired data integrity protection), at block 304.
This step will be explained in greater detail hereinafter with reference to FIG. 1 OA and FIG. l OB, which is a cor~ ion of FIG. l OA.
2s Finally, the FIG. 3 overview depicts the pl~r~llc;d process steps of being able to recover from (i.e., insure data integrity following) a power loss condition (as shown at block 305); and recover from a RAM loss condition (as shown at block 306).
These steps will be explained in greater detail hereinafter with reference to FIG. 11 and FIG. 12, respectively.
The RAM loss recovery feature (described with reference to FIG. 12), although being desirable and being included in the preferred embodiment of the invention, is considered an optional feature of the invention.
CA 02214~1~ 1997-09-03 wo 96l34336 PCT/US9610S676 Prior to setting forth a detailed description of the methods conl~lllplated by the invention, with specific reference to FIGS. 7-11; an explanation of suitable, albeit exemplary, logical layout for a DOS created set of disk (or memory card) file control structures; an exemplary logical layout for each of the data files being recorded and s protected; and an exemplary logical layout for each data block in a given data file, will be set forth immediately h~-,hlarl~l with reference to FIGS. 4-6, respectively.
As indicated hereinbefore, FIG. 4 depicts (in accordance with the te~çhinp~s of one embodi~nent of the invention), an exemplary logical layout for a DOS
created set of disk (or memory card) file control structures. Those skilled in the art will readily appreciate how to utilize DOS to create such file control structures.
Accordingly, the structures depicted in FIG. 4 are shown for the sake of completeness only, with the details of how the structures are created being considered well within the purview of those skilled in the art without the need for further explanation.
In particular, Fl[G. 4 shows the key DOS created control structures that must be protected to insure the integrity of the disk (again, ~csllming DOS is the utility used for file creation and management), narnely: the DOS boot record, shown in FIG. 4 by reference nllmer~l 401; the File Allocation Tables (FAT), two of which are shown in FIG. 4 by reference numeral 402; and the DOS Root Directory, shown in FIG. 4 by reference numeral 403.
The aforementioned DOS control structures provide basic DOS operating system access to the disk and all of its files.
FIG. 4 also shows a set of n files (shown via reference numerals 404-1 thru 404-n) created by the file creation and management utility. According to one embodiment of the invention, the data files are created by the user during the data storage initialization process shown at block 303 in FIG. 3 (to be explained in detail hereinafter with reference to FIG. 9). The number of files (and consequently, the amount of disk space to be used) may be specified by the user.
An additional control structure that is optionally created by the user, and - must be protected when created (although not created by DOS), is the "static header", which may be seen with reference to FIG. 5 (reference numeral 501). The optionalstatic header provides memory for the storage of process dependent inforrnation specified by the user, such as (for example) information that defines the internal CA 02214~1~ 1997-09-03 structure of individual files. According to the ~.ercl.ed embodiment of the invention, the static header is written once, during the aforementioned data storage initi~li7~tion process.
Those skilled in the art will readily appreciate that the aforementioned s control structures can only be corrupted during an operation which writes to the disk.
The data integrity protection techniques conteTnrlated by the invention protects these structures by elimin~ting the need to write to them after the aforementioned data storage initi~li7~tion process (shown at block 303 in FIG. 3 and explained in detail hereinafter with reference to FIG. 9), has been completed.
o Further reference should be made to FIG. 5 which depicts the elements of an exemplary logical layout for each of the data files depicted in FIG. 4.
In particular, FIG. 5 depicts (in a~ ition to the aforementioned ~.efe..~d (but optional) static header block SOl; a preferred (but optional) block recovery area, 502; and m data blocks shown as blocks 503-1 thru 503-m.
The optional block recovery area, according to the plcr~,lcd embodiment of the invention, is used to m~int~in a "duplicate" block image on disk for memory loss recovery processing purposes (to be explained in detail hereinafter with reference to FIG. 1 OB, FIG. 11 and FIG. 12). The block recovery area (if configured and used) is updated as needed during the online data storage process (explained in detail hereinafter with reference to FIG. lOB).
The actual data blocks depicted in FIG 5 (via reference numerals 503-1 thru 503-m), are also updated as needed during the online data storage process.
Reference should now be made to FIG. 6 which, as indicated hereinbefore, depicts an exemplary logical layout for each data block depicted in FIG. S.
2s In particular FIG. 6 depicts block checksum 601; block sequence number 602; record count 603; and actual data records 604-1 thru 604-3.
Block checksum 601 is a check value which may optionally be used (and is used in a ~-lcre.-cd embodiment of the invention) to determine if a block transfer is sllcces~ful.
Block sequence number 602 is sequentially assigned numerical value which may be used to properly insert a recovered block, in the sequence of blocks in a - / CA 0221451C. 1997-09-03 WO 9613J.336 P<_T~T7S96/~S6 ,-~6 -15- -'. , ;;
given file on the mediuln, following a RAM loss condition, as will be explained in greater detail hereinafter with reference to FIG 12.
Record count 603 is a numerical value indicative of the nurnber of records in a given block within a file. For the exarnple depicted in FIG. 6, record count 603 would be set to 3 indicating the presence of the three records illustrated (604-1 thru 604-3) Finally, before turning to the detailed description of the methods contemplated by the invention, with specific reference to FIGS. 7-12, it should be noted that in addition to the data integrity protection techniques contemplated by the invention lo elimin,.tin~ the need to write to the above described (disk resident) control struc~ures after the aforementioned data storage initialization process (explained with reference to FIG. 9) has been completed; another key factor in m~int~ inin~ data integrity, in accordance with the teachings of the invention, is the ability to restart the data storage system (removable medium) following a CPU reset or power down condition.
According to the preferred embodiment of the invention, this restart capability is realized by: (a) maintaining data records in the recording instrument's internal memory (preferably a backed memory such as backed RAM) until the records have been successfully transferred to disk; (b) m,.n;~E~in~ the data storage and disk update processes using a series of atomic "go/no-go" operations to prevent corruption of data blocks; and (c) m~int~ininE a "duplicate" block image on disk for performing the aforementioned (optional) memory loss recovery processing in the event of a RAM loss condition.
According to the preferred embodiment of the invention, the steps listed above (steps (a)-(c)) are employed when implementing the preferred illustrative processes described hereinafter with reference to FIGS. 7-12. Those skilled in the art will recogruze that the sequence of certain steps in the illustrative processes themselves (the processes depicted and described with reference to FIGS. 7-12), may be altered;
that certain of the illustrated process steps may be elimin~.ted (for example, where optional RAM loss condition processing is not practiced)~e~ ;~ ut dcEsr" l;"~ "Athc s~opc or .pirit of tho in~*~tion ~ hich is intcndcd t~ bc limitod only by tho 013 m6 app~nd~d-h~rot~
Ai',~ ,r, S,-IE~r WO gf '3~ 6 PCrlUS96/OS676 Reference should now be made to FIG. 7 which depicts, in accordance with the te~hing~ of one embodiment of the invention, an illu~LIdLivt; set of process steps for form~t~ing the storage medium.
In particular, FIG. 7 depicts the form~ttinp; process as including the 5 following steps: de~r.~ if the m~ m~ is ~r~,~ell~y inserted in the instrument (step 701); ~ g if the micro switch door (door 107 shown in FIG. 1) is closed (step 702); form~tting the medium itself (using, for example, a file m~n~gement utility such as DOS), if the medium is p~ CI ly inserted in the instrument (step 703); and then del~ i-.g if the format operation was p~,iro~ ed succe~fully (step 704). If the results o of any of the aforementioned steps of dt;te ;nil-g is negative, a "Format Failed" report is shown generated at step 705.
The actual step of form~tting the media per se (step 703) prepares the disk for both physical and logical access under the exernplary DOS ~ dLillg system.
During the forrnat process all sectors of the disk are tested for both read and write s access. "Bad" sectors are identified as being bad in the DOS File Allocation Tables (FAT). The DOS Boot Record is also created during format.
According to the invention, the forrniqtting process described with reference to FIG. 7, must be performed prior to the data storage initi~li7~tion process described hereinafter with reference to FIG. 9.
Reference should now be made to FIG. 8 which depicts, in accordance with the te~chin~ of one embodiment of the invention, an illustrative set of process steps for configuring non-volatile memory with a set of storage operation parameters.
The user must configure the parameters under which the storage system will operate. These parameters include (for a typical process data recording system): (a) the type of data to be stored (process data, alarms, events, etc); (b) the data points to be stored; and (c) the rate of storage. Those skilled in the art will realize that this list of parameters is set forth for the sake of illustration only and that a fewer or greater nurnber of parameters may be a~ liate depending on the application in which the recording instrument is being employed.
According to the ~l~;r~llc;d embodirnent of the invention, the configuration information (user setup information) is stored in a non-volatile memory device, such as an EEPROM. As indicated hereinbefore, the term CA 02214~1~ 1997-09-03 W~ 96134336 I''CT/USg6/OS676 "non-volatile memorv" refers (in addition to the exemplary EEPROM), to ROM, PROMand any other type of memory device that m~int~inc its content without power. The setup information is used to partition the disk during the data storage initi~li7~tion process described helei-l~rl~,L with reference to FIG. 9.
The illu~LIdLiv~ process for performing the configuration process described hereinabove may be seen, with reference to FIG. 8, to include steps for ~eeiryil.g the aforementioned application dependent par~m~ters (shown p~lrol..led at steps 801-803 for the specific illu~lldLivti ~,..,.-,t~ iccllcce(1 hereinabove); and storing the specified parameters in non-volatile memory (step 804, with EEPROM being 0 used as an exemplary form of non-volatile memory).
The further step of verifying that storing the specified parameters in non-volatile memory was s~lccç~ful, is shown as step 805 in FIG. 8. In the event that the storage operation does not succee~l, a "EEPROM Failed" report is shown generated at step 806.
Reference should now be made to FIG. 9 which depicts, in accordance with the tç~hingc of one embodiment of the invention, an illustrative set of process steps for initislli7ing the storage metlillm (referred to hereinbefore as p~lrO.~ g data storage initiali_ation).
The primary purpose of initi~li7~tion is to prepare the disk for secure data storage operation. The non-volatile user setup information tells the initi~li7~tion process how to partition the disk.
According to the illustrative embodiment of the invention depicted in FIG. 9, the following actions are performed during initi~li7~tion: read the data storage configuration stored in non-volatile memory (step 901);
~let~rmine the file allocation requirements (step 902) from the configuration data, specifically the number of files needed and file size as specified by the user (or otherwise derived by the data processing device included in the l~coldillg instrument) during setup, and then create the actual files on the disk, including writing file control information to the storage medium (step 903).
The further step of verifying that the write operation was suc cçccful, is shown as step 904 in FIG. 9. In the event that the write operation does not sl~ccee~l, a "INIT Failed" report is shown generated at step 905.
CA 02214~1~ 1997-09-03 WO 96134336 r~ r ~ l 5ti76 FIG. 9 goes on to illustrate steps directed to creating and storing the aforementioned (optional) static header onto the disk.
Where the static header is used, the header inforrn~tion is shown written to disk at step 906; followed by the step of verifying that the write operation pt;,ro~ ed at step 906 was succe~ful (at step 907). Again, an "INIT Failed" report is showngenG.~d (at step 908) if the ~,vrite to disk of the static header was lm~llGces~fill Finally, FIG. 9 goes on to show the step of clearing the data area within the files (step 909) as an added ~ r.,.,~d step (not l-~cess~. y in all embo(1im~nte of the invention) to insure file integrity. For example, the step of clearing could be p~,r~"",ed o by writing all zeros to the file space. An "INIT Failed" report is also generated (step 91 1 ) if the clearing operation (when employed) is unsuccessful.
Once again, according to the invention, disk space allocation is performed during the above described initi~li7~tion process only. This means that no further write-access the various illustrative control structure discussed hereinabove (the Boot Record, FAT, Root Directory, or Static Header) will be performed for this disk.
Also, no data blocks are written to the disk until the initialization process is complete.
Reference should now be made to FIG. 1 OA and FIG. 1 OB which depict, in accordance with the te~~hinp~ of the invention, an illustrative set of process steps for ~n~n~gin~ the data transfer process contemplated by theinvention.
As indicated hereinabove, the recording instrument contemplated by the invention m~int~in~ a series of data block structures in RAM memory (preferably backed RAM) that are used to stage the data records prior to their storage on disk. Each data block structure contains an exact image of a data block on the disk. The size of each Data Block is preferably selected to match the allocation unit of the disk (512 bytes for a 1.44 Mbyte floppy disk or a 512K memory card). This would tend minimi~ loss of data if corruption occurs.
In order to prevent the corruption of the data block structures in RAM, and to provide a secure transfer of the data record to the disk (and be able to detect the corruption of data block structures transferred to disk), the following proce~ing and fee-lb~l k sequence (depicted in FIG. lOA and continued in FIG. lOB) may be used:
determine if there exists any process data received and/or derived by the instrument CA 02214~1~ 1997-09-03 WO 96134336 PCT/U~ SC76 waiting to be stored in the RA~ (shown as step 1001 in FIG. lOA); build data records from any process data waiting to be stored (step 1002); write a record created at step 1002 to a predefined RAM data block (step 1003); keep track of the number of records built and stored by, for example, incremçntin~ a record count to officially add the record S the data block (step 1004); assign a block sequence number, preferably calculate the aforementioned block checksum (described hereinbefore with reference to FIG. 6), and store both of these values in the block (step 1005); mark each block that is ready for transfer to the medium with an indication that it is ready for l~ sr.,. (step 1006), by for example setting a flag associated with the block stored in RAM; cletçrrnin~?, whenever 10 the removable medium is to be periodically up-l~te-l (an option; not a requirement to practice the inveNtion), if it is time for the periodic update (step 1007); deterrnine if there are blocks in RAM waiting to be L~ r~ d (step 1008); fletermine whether or not the removable medium is l~lu~ ly inserted in the instrument, i.e., for the a~.~dlus depicted in FIG. 1 and FIG. 2, clet~rmine if the micro switch door closed with the 15 removable medium properly inserted therein (step 1009); write a data block awaiting transfer to the removable storage medium (step 1010) if the removable media is properly inserted in the instrument; determine if the write operation was s-lcccs~ful (step 1011), by, for example, reading the aforementioned check sum value (if created and stored in the data block), and mark the data block in RAM as "Transfer Completed" to 20 indicate the transfer was complete whenever it is cletçrmined by step 1011 that the write operation to disk was successful (step 1012).
With respect to performing step 1010 in FIG. 1 OB (the step of write a data block awaiting transfer to the removable storage medium), what is implied, although not specifically shown in FIG. 1 OB, is that the write is to two places in a given 2s file when the aforementioned block recovery option is used; namely to the block recovery area first and then the given data block itself.
By lltili7ing the ~lcre..ed process depicted in FIG. lOA and FIG. lOB, m~rking the block in RAM as "Transfer Completed" (step 1012), completes the fee~lb~k path required to deterrnine a sllçce~ful write to disk has occurred.
If the write fails, the block will remain marked as awaiting transfer, and will be m~int~ined in the intern~l RAM (preferably backed RAM), until the next update _ CA 02214~1~ 1997-09-03 WO 9~'3 1~36 PCTIUS96/OS676 cycle or asynchronous attempt (depending on application) is made to write to disk agam.
When cyclic updating of disk is performed, the cycle will be repeated at periodic intervals until the block has been sllccçc~fully transferred to disk, at which 5 point in time the block will have been marked as "Transfer Completed". After a block is m~rketl as "Transfer Completed" it may be cleared and recycled as needed. Those skilled in the art will readily appreciate that the periodic update option is useful in preserving the life of certain types of removable storage media (e.g., a floppy disk).
As indicated hereinabove, if the memory loss recovery option is used, lo each data block will be written to the disk file twice: once to the normal data area, and once to the special block recovery area. The duplicate block will be used to restore the corresponding block in the data area in the event that RAM is lost during a power-down, as will be explained in greater detail hereinafter with reference to FIG. 12.
Reference should now be made to FIG. 11 which depicts, in accordance I s with the te~l~hing~ of one embodiment of the invention, an illustrative set of process steps for recovering from a power loss condition.
According to the ~cr~ ;d embodiment of the invention, all untransferred blocks in the RAM area upon a restart (blocks marked as awaiting transfer) are located and then writes to disk are attempted for each such block. This 20 resumes the feedback process described hereinbefore. If a data block on disk had been corrupted because of a power down, this process will restore it by ovc. ~vfili"g it with the RAM-resident copy.
More particularly, with reference to FIG. 1 1, an exemplary set of process steps contemplated by the invention to perform the aforestated functions include:
25 det~rmininE, after a power loss condition, if the non-volatile memory was previously configured (step 1 101 ); det~nnining if there are any data blocks that are marked as awaiting transfer to the removable medium (step 1102); cletennining if said medium is properly inserted in said instrument, i.e., inserted in the ,~co.di,lg instrument with door 107 closed when using an instrument of the type depicted in FIG. 1 (step 1 103); writing 30 a block awaiting transfer to a target file on the medium to the recovery area of the target file, if the optional recovery area rli~c~-~se-l hereinbefore (shown at 502 in FIG. 5) is used (step 1 104); writin~ a block awaiting transfer to a target file on the medium, to the CA 022l4~l~ l997-09-03 WO9~'3~ 6 PCI/US96/OS676 data storage portion (shown, for example, at 503-1 in FIG. 5) of the target file (step 1105); .1~ if the write operations ~,.ro-l--ed in step 1104 (if ~ ro----ed) and step 1105 were sllcces~ful (step 1106); mslrkinp each data block s~lcces~fillly transferred to the medium to indicate the transfer was complete whenever it is ~ l in step s 1106 that the write operation(s) was (were) ~llcces~ful (step 1107); and ~l~l. ...;..;..~ if all blocks have been PY~mined subsequent to experiencing a given loss of power condition (step 1108).
R~r~.~..ce should now be made to FIG. 12 which depicts, in accordance with the t~rllin~s of one embodiment of the invention, a set of exemplary process steps o for recovering from a RAM loss condition, as defined hereinbefore.
If the capacitor-backed RAM (or RAM which is not backed) has been lost, the ex~mpl~ry memory loss recovery process set forth htl~i-.arL~l can be used to attempt to restore and/or repair a corrupted data block on disk.
The process involves the following steps which are ill~letr~te(l in FIG. 12:
det~rminin~, after a RAM[ loss condition has occurred, if the non-volatile memory was previously configured and the security micro switch is closed (step 1201); if so, finding the logical last data block in each disk file (step 1202) to determine if corruption has occurred (step 1203) by, for example, testing the block checksum value; and (if corruption has occurred), the contents of the "duplicate" block in the aforementioned recovery area (if this option is used), should be copied into the logical last data block, ovel ~vliLil1g the corrupted contents of the logical last data block (step 1204).
Not shown in FIG. 12, since it con~ uLes an ~ltPrn~te embodiment of the invention, the co-- ~ed logical last data block could be "repaired" if no copy were m~int~ined in the recovery area. A block could be ",e~ai.ed", for example, by assigning 2s the next logical sequence number to the block being repaired; setting its record count to zero; calculating a block checksum value; and then rewriting the "repaired" block to disk.
The illustrative process depicted in FIG. 12 continues with steps 1205-1209 only if (1) the block recovery area option is used; and (2) a dçtermin~tion at step 1203 is made that a given data block is not colTupted. In particular, steps 1205-1209 involve: dçterminin~ if the data block written in the recovery area (now assumed to be used) for the file is newer than the logical last block (step 1205); determinin~, whenever WO 96/34336 ,~ J~6/0~;'6 . ., it is deterrnined at step 1205 that the data block written in the recovery area for the file is newer than the logical last block, if the sequence nurnber for the data block written in the recovery area equals the sequence number for the logical last data block (step 1206);
copying the data block written in the recovery area for the file into the last logical data s block whenever it is deterrnined in step 1206 that the sequence nurnber for the data block written in the recovery area equals the sequence nurnber for the logical last data block (step 1207); deterrnining, whenever it is deterrnined in step 1206 that the sequence number for the data block written in the recovery area does not equal the sequence nurnber for the logical last data block, if the sequence nurnber for 10 the data block written in the recovery area is greater than the sequence nurnber for said logical last data block (step 1208); and adding the data block written in the recovery area at the logical end of the given file whenever it is deterrnined at step 1208 that the sequence nurnber for the data block written in the recovery area is greater than the sequence nurnber for the logical last data block (step 1209).
The process depicted in FlG. 12 concludes with step 1210, which follows the performance of any of steps 1204, 1207, 1208 or 1209 (arrived at based on Ihe results of the various deterrninations made at steps 1203, 1205, 1206 and 1208 shown in FIG. 12), which causes the process depicted in FIG. 12 to be iterated when files remain 20 to be examined (after a given pass through the FIG. 12 process), following the occurrence of a RAM loss condition.
What has been described in detail hereinabove are methods and apparatus which meet all of the aforestated objectives. As previously indicated, those skilled in the art will recognize that the foregoing description has been presented for the sake of 25 illustration and description only. ¦Tt S ~IOt intehdcd to bc oxh~ti~o ar to li...i~ tho invf~r.~;~ .h,. pr~ r '-;'cc~ tcb~ o~ mnnyrr.odi~l~6~noond Vz~7.~ ti~ 7r~ r~cc~;~1~ ;r 1~~ r ~ bo~ ~hir~
For example, the aforementioned teaching for protecting the integrity of process data transferred to and stored on a removable 30 storage media, associated with a programmable stand alone data recording instrument, may be applied to protect the integrity of process data transferred to and stored on fixed storage media (installed or external) associated with such instruments.
,rl WO 9o'/3433~6 rCI'/U~:;95/05~'7O .
' ! -23- ' ,''' ~' The embodiments and examples set forth herein were presented in order to best explain the principles of the instant invention and its practical application to thereby enable others skilled in the art to best utilize the instant invention in various embodiments and with various modifications as are suited to the particular use 5 contemplated.
~ LI vi ~i of thc ~1~0V~ , bc undcr~too=~
appended hereto are intended to cover all such m~iD~ariations which fall within the true scope = ,~
process.
When the nature of a given recol~lillg instrument and the recording environrnent permits, assuring data integrity on removable storage media (and recognizing that a problem may exist), can be as simple as an on site operator observing that a power failure has occurred or that a plug has been removed from a wall socket;
observing that a warning appears on a colll~uLe~ display screen should, for example, a floppy disk be removed prior to an in progress data transfer being completed; or using hardware and software solutions, such as the aforementioned UPS andlor software for CA 02214~1~ 1997-09-03 WO 96/34336 PCT/U~''rr~76 providing the aforementioned on screen warnings to an operator, etc., to recognize potential problems and protect data integrity.
The problems associated with ~sl~ring data integrity for data stored on removable storage media in opeldlor ~ttentle~l mainframe or PC coll.~u~hlg s environment~, and even for process data recording envh~ol.l.lell~ in which an operator ~elrolllls "one-shot" utility type lecordillg and is physically present to observe and control the data recording process; differ considerably from the problems experienced when trying to assure the inleg-ily of process data being recorded on removable storage media by often lm~tt~n~le~l, field located, "stand alone" recording instruments (defined herein as instruments not requiring full time o~e.dlol supervision or interaction to actually perform the data recording function), which is the type of recording instr -ment~tion in which the present invention finds utility.
In the aforementioned environment in which the invention finds utility, the removable storage media rather than being used in the previously mentioned "one l s shot" utility type recordillg context, is typically used as a continuous storage medium.
Furthermore, in the aforementioned environment in which the invention finds utility, UPSs are normally unavailable or too costly to provide data integrity protection; and operators do not normally attend the recording device over the whole continuous recording period which can run for days, weeks and even longer periods of time.
In view of the above, in the context in which the present invention finds utility, the problem of ~nring the integrity of data recorded on the continuous medium is compounded by the fact that the safeguards of either being under assured continuous power and/or direct operator supervision, are not necess~rily present.
Accordingly, it would be desirable to provide methods and d~ lldLLIS for 2s assuring the integrity of process data stored on a removable storage media associated with stand alone data recording instruments being used to continuously record process data.
Furthermore, it would be desirable to provide methods and apparatus for ~sllrin~ the integrity of process data stored on a removable storage media in a manner that does not require the use of an e~t~rn~l power source, such as an Uninterruptible Power Supply (UPS).
-CA 02214~1~ 1997-09-03 3 ~ ;', Still further, it would be desirable to provide methods and apparatus for assuring the integrity of process data stored on a removable storage media in a manner that does not require the full time presence of an operator to manage and observe the data recording process per se.
s Further yet, it would be desirable to provide methods and apparatuswhich enable process data which has been corrupted during a power loss or CPU reset, to be recovered when norrnal operation of a recording instrument resumes.
SUMM~RY OF THF. INVFNTION
The present invention provides a method as defined in Claim I
o hereinafter.
The present invention also provides a method as defined in Claim 23 hereinafter. The present invention also provides apparatus as defined in Claim 24 hereinafter.
The present invention may provide any one or more of the features of dependent Claims 2 to 22 or Claims 25 and 26 hereinafter.
Thus, the invention may provide methods and apparatus for assuring the integrity of process data stored on a removable storage media associated with stand alone data recording instruments being used to continuously record process data.Furthermore, the invention may provide methods and apparatus for assuring the integrity of process data stored on a removable storage media in a manner that does not require the use of an external power source, such as an Uninterruptible Power Supply (UPS).
Still further, the invention may provide methods and apparatus for assuring the integrity of process data stored on a removable storage media in a manner 2s that does not require the full time presence of an operator to manage and observe the data recording process per se.
Further yet, the invention may provide methods and apparatus which enable process data which has been corrupted during a power loss or CPU reset, to be recovered when normal operation of a recording instrument resumes.
The information on the removable medium may be protected against two basic causes of lost data: corruption of the file control structures for the medium, and corruption of the data control structures within a file.
~MEl~lDED SHET
CA 02214~1~ 1997-09-03 Most file creation and management utilities, such as DOS, IJNIX, etc., do not provide any inherent mechanism for assuring the integrity of file controlstructures transferred to a removable storage medium. However, according to one aspect of the invention, the file control structures can be protected by allocating file 5 space on the medium during a one-time initialization procedure. Furthermore, according to the invention, no storage of process data is permitted until initialization has been successfully completed. The instrument will continue to accumulate process data in an internal memory (e.g., internal random access memory (RAM)), while initialization is taking place.
BR~EF DESCRIPTION OF THF DRAWrNG
FIG. 1 depicts an exemplary programmable process data recording instrument of the type contemplated by one aspect of the invention for use in conjunction with a removable floppy disk.
FIG. 2 depicts a further exemplary programmable process data recording 15 instrument of the type contemplated by the invention for use in conjunction with a removable PCMCIA memory card.
FIG. 3 depicts an overview of the data integrity protection process contemplated by a preferred embodiment of the present invention.
FIG. 4 depicts, in accordance with the teachings of one embodiment of 20 the invention, an exemplary logical layout for a DOS created set of disk (or memory card) file control structures.
FIG. S depicts, in accordance with the teachings of one embodiment of the invention, an exemplary logical layout for each of the data files depicted in FIG. 4.
DF~~~ S~ ~r-~
CA 02214~1~ 1997-09-03 FIG. 6 depicts, in accordance with the te~t~hinge of one embodiment of the invention, an exemplary logical layout for each data block depicted in FIG. 5.
FIG. 7 depicts, in accordance with the te~rhin~e of one embodiment of the invention, an illustrative set of process steps for form~ltinP the storage m~ m .
FIG. 8 depicts, in acco~ ce with the te~rhinge of one embodiment of c the invention, an illustrative set of process steps for configuring non-volatile memory with a set of storage operation p~r~m~t~rS.
FIG. 9 depicts, in accordance with the te~rhin~s of one embodiment of the invention, an illustrative set of process steps for initi~li7.ing the storage medium.
0 FIG. 10A and FIG. 10B depict, in accordance with the te~chinge of one embodiment of the invention, an illustrative set of process steps for m~n~ging the data transfer process co~ lated by the invention.
FIG. 11 depicts7 in accordance with the te~rhing~ of one embodiment of the invention, an illustrative set of process steps for recovering from a power loss condition.
FIG. 12 depicts, in accordance with the tto~rllingc of one embodiment of the invention, an illustrative set of process steps for recovering from a RAM loss condition.
nF,TATT,F,n nF,SCRllPTION
Prior to describing the details of the a~ lldtUS and process steps contempl~ted by the invention, certain assumptions and definitions which have been made for the sake of illustration and convenience in providing this detailed description will be explained.
The term "disk" is used herein as a generic reference to the aforementioned removable storage medium. Those skilled in the art will readily appreciate that the processes set forth herein will work for any properly formsltted devices (where the DOS format is used for the sake of illustration herein), including floppy disks (of any density), PCMCIA memory cards, etc.
As indicated hereinabove, the invention is presented, for the sake of illustration only, ~eel-ming that DOS is the file creation and management utility used for pro~ ly form~t~ing the storage medium. Those skilled in the art will readily appreciate that other commercially available and/or user developed file creation and management -CA 02214~1~ 1997-09-03 _g _ utilities (e.g., I~NIX, etc.), may be used to practice the invention after making a~ l.ate modifications to take into account the utility dependent file control structures associated with a given utility.
Furthermore, the invention is set forth in the context of a stand alone 5 lCCOldillg i~ ent (to be described in detail hc.~inar~r with reference to FIG. 1 and FIG. 2), assumed to include random access memory (RAM) within which process is d for data transfer to tlhe removable metlillm and stored, at least te~ ol~;ly, prior to l~ r~r to the medium.
According to the invention, the RAM is preferably backed (for example, 10 a capacitor backed RAM), to insure that if P~tPrn~l power to the instrument is interrupted the ~AM contents will be m~int~in~l for (in the exemplary capacitor backed RAM in~t~n~e) the discharge life of the capacitor (e.g., ~loxill~alcly 90 minllte~ in one embodiment of the invention). Again, it is not nrce~ry for the RAM included in the recording h.sL.~unent in which the invention is practiced to be backed; but it is 15 preferable to increase the units ability to protect the illlegl;ly of process data being stored prior to succes~ful transfer; and for providing a process data back up after data is transferred.
Finally, the stand alone recording instruments in which the invention may be practiced are assumed to be "progr~mm~ble" devices; that is, devices that are 20 provided with access to (and execute) programs which implement the various processes described herein to protect the integrity of the data being recorded on the removable storage media.
Specific examples of commercially available stand alone lccolding devices of the type cont~rnplated by the invention (used to record process data) are 2s microprocessor based video recorders and controllers available from Leeds & Northrup Company.
Those skilled in the art will readily be able to implement the processes described herein in the form of programs suitable for execution by a microprocessor, ~C~sllming a knowledge of the file creation and management utility being employed 30 (such as the exemplary DOS utility) and having the benefit of the various flow charts depicted in the Drawing.
CA 02214~1~ 1997-09-03 WO 9f '31~36 PCI~/US96/05676 Reference should now be made to FIG. 1 which, as indicated hereinbefore, depicts an exemplary programmable process data recordillg instrument of the type contemplated by one aspect of the invention for use in conjunction with a removable floppy disk.
s In particular, exemplary programmable process data l~cul~dillg instrument 100 shown in FIG. 1 depicts the device as inl~hl-ling: pro r~Tnm~ble data procç~ing means 101 shown, by way of example, as a microprocessor; Input/Output (I/O) means 102, coupled to programmable data processing means 101 via link 150, for leceivhlg raw process data input to said instrument via exemplary wiring connections l S 1 (where 0 I/O means 102 as depicted in FIG. 1 may be any one of a number of well known circuit devices for me~ ring process data input); memory means 103, coupled to programmable data proces.cing means 101 via link 152, for at least temporarily storing raw process data (received over links 150, l S l and 152), and/or process data derived by the instrument itself (derived via programmable data proces~ing device 101);
15 non-volatile memory means 104, shown coupled to the programmable data processing means via link 153, for storing a set of configuration parameters used to configure the removable media; media interface means 105, shown coupled to programmable data proces~ing means 101 via link 154, for receiving the removable storage medium when properly inserted therein and making the storage medium available to programmable 20 data proces~ing means 101 for data transfer operations; and means for generating a signal, 106, to programmable data processing means 101 whenever the removable media is not properly inserted in media int~ ce means 105, to thereby enable programmable data processing means 101 to recognize a condition in which data transfer operations between memory means 102 and the removable storage medium is to 25 be inhibited.
An example of the aforementioned "means for generating a signal"
(reference numeral 106), is depicted in FIG 1 as a micro-switch arrangement (a switch 1 06a and switch activator 1 06b), for generating a software detectable signal (detectable by software running on programmable data processing device 101), whenever front door 30 107 of the instrument (through which the removable media is installed and removed) has been opened.
-CA 02214~ i 1997-09-03 WO 9r'31~76 r~ /0S676 As intlic~ted hereinbefore, in accordance with one aspect of the invention, upon detection of a "door open" condition (i.e., whenever switch activator 106b is not c~ in~ switch 106a to be activated), software contemplated by the preferred embodiment of the invention (running on programmable data proces~in~ device 101 ) 5 will immc~ tely stop any further transfer of data to or from the removable storage medium. This action p~ lL~ the potential loss of data due to manual removal of the storage m~ lm while data transfer is taking place. Data storage, according to the t~ in~s of the invention, will not resume until door 107 has been closed.
It should be noted that if door 107 is opened during a disk data transfer, 0 the software will complete the llansfer and then inhibit any further disk activity. The latency in the depicted exemplary system is approximately 100 milliceconds, which will allow the software to safely complete an active data transfer prior to ejection of the disk.
According to a ~l~rell~d embodiment of the invention, in~llumGlll 100 will continue to A~ccllm~ te process data in internal memory 103 while a data transfer 5 initi~li7~tion process (to be explained hereinafter) takes place.
Furthermore, according to a ~lc;r~ ed embodiment of the invention, the information in exemplary RAM memory 103 may be m~intslin~ should a power failureoccur through the use of a capacitor-discharge battery device, such as device 120 depicted in FIG. 1.
Finally, it should be noted that according to a ~lc;rell~d embodiment of the invention, although not depicted in the Drawing, software programs implementing the processes taught hereinafter are embedded in a read only memory (ROM) accessible to programmable data processing device 101. It should be further noted that the 25 invention is not inten(le~l to be limited to this preferred (ROM) program storage me-~h~ni~m Reference should now be made to FIG. 2 which, as indicated hereinbefore, depicts a further exemplary progr~mm~ble process data recording - instrument of the type contemplated by the invention for use in conjunction with a 30 removable PCMCIA memory card.
In particular, FIG. 2 is identical to FIG. 1, with the exception that a PCMCIA card interface, 201, is shown within recording instrument 200.
CA 022l4~l~ l997-09-03 Reference should now be made to FIG. 3 which, as indicated hereinbefore, depicts an overview of the data integrity protection process contemplated by a pLerell~d embodiment of the present invention.
The illustrative process depicted in FIG. 3 is shown to include steps 5 directed to addressing three major considerations: (1 ) pr~dlion of the removable storage medium and int~rn~l instrument storage facility (e.g., RAM), to support data integrity plole~;lion; (2) m~n~ging the data ~ ,r.. process per se to achieve the desired data integrity protection; and (3) leco~,cl~ operations (with some recovery fe~Lules being optional, as will be explained hel~ &rl~ following a power loss condition and/or a lo RAM loss condition (e.g., where RAM fails due to a power outage, expiration of a battery backed power window, etc.).
More particularly, the process overview depicted in FIG. 3, for that portion of the process dealing with the pr~ alion of the removable storage medium and intern~l instrument storage facility to support data integrity protection, includes 1S steps of: form~tting the removable storage m~ lm (shown at block 301); configuring the storage parameters (shown at block 302); and initi~li7in~ the storage system (shown at block 303).
Each of aforementioned steps (shown at blocks 301, 302 and 303) will be exrl~ine~l in greater detail hereinafter with reference to FIG. 7, FIG. 8 and FIG. 9, respectively.
The FIG. 3 overview goes on to depict the step of m~n~ging the data transfer process per se (to achieve the desired data integrity protection), at block 304.
This step will be explained in greater detail hereinafter with reference to FIG. 1 OA and FIG. l OB, which is a cor~ ion of FIG. l OA.
2s Finally, the FIG. 3 overview depicts the pl~r~llc;d process steps of being able to recover from (i.e., insure data integrity following) a power loss condition (as shown at block 305); and recover from a RAM loss condition (as shown at block 306).
These steps will be explained in greater detail hereinafter with reference to FIG. 11 and FIG. 12, respectively.
The RAM loss recovery feature (described with reference to FIG. 12), although being desirable and being included in the preferred embodiment of the invention, is considered an optional feature of the invention.
CA 02214~1~ 1997-09-03 wo 96l34336 PCT/US9610S676 Prior to setting forth a detailed description of the methods conl~lllplated by the invention, with specific reference to FIGS. 7-11; an explanation of suitable, albeit exemplary, logical layout for a DOS created set of disk (or memory card) file control structures; an exemplary logical layout for each of the data files being recorded and s protected; and an exemplary logical layout for each data block in a given data file, will be set forth immediately h~-,hlarl~l with reference to FIGS. 4-6, respectively.
As indicated hereinbefore, FIG. 4 depicts (in accordance with the te~çhinp~s of one embodi~nent of the invention), an exemplary logical layout for a DOS
created set of disk (or memory card) file control structures. Those skilled in the art will readily appreciate how to utilize DOS to create such file control structures.
Accordingly, the structures depicted in FIG. 4 are shown for the sake of completeness only, with the details of how the structures are created being considered well within the purview of those skilled in the art without the need for further explanation.
In particular, Fl[G. 4 shows the key DOS created control structures that must be protected to insure the integrity of the disk (again, ~csllming DOS is the utility used for file creation and management), narnely: the DOS boot record, shown in FIG. 4 by reference nllmer~l 401; the File Allocation Tables (FAT), two of which are shown in FIG. 4 by reference numeral 402; and the DOS Root Directory, shown in FIG. 4 by reference numeral 403.
The aforementioned DOS control structures provide basic DOS operating system access to the disk and all of its files.
FIG. 4 also shows a set of n files (shown via reference numerals 404-1 thru 404-n) created by the file creation and management utility. According to one embodiment of the invention, the data files are created by the user during the data storage initialization process shown at block 303 in FIG. 3 (to be explained in detail hereinafter with reference to FIG. 9). The number of files (and consequently, the amount of disk space to be used) may be specified by the user.
An additional control structure that is optionally created by the user, and - must be protected when created (although not created by DOS), is the "static header", which may be seen with reference to FIG. 5 (reference numeral 501). The optionalstatic header provides memory for the storage of process dependent inforrnation specified by the user, such as (for example) information that defines the internal CA 02214~1~ 1997-09-03 structure of individual files. According to the ~.ercl.ed embodiment of the invention, the static header is written once, during the aforementioned data storage initi~li7~tion process.
Those skilled in the art will readily appreciate that the aforementioned s control structures can only be corrupted during an operation which writes to the disk.
The data integrity protection techniques conteTnrlated by the invention protects these structures by elimin~ting the need to write to them after the aforementioned data storage initi~li7~tion process (shown at block 303 in FIG. 3 and explained in detail hereinafter with reference to FIG. 9), has been completed.
o Further reference should be made to FIG. 5 which depicts the elements of an exemplary logical layout for each of the data files depicted in FIG. 4.
In particular, FIG. 5 depicts (in a~ ition to the aforementioned ~.efe..~d (but optional) static header block SOl; a preferred (but optional) block recovery area, 502; and m data blocks shown as blocks 503-1 thru 503-m.
The optional block recovery area, according to the plcr~,lcd embodiment of the invention, is used to m~int~in a "duplicate" block image on disk for memory loss recovery processing purposes (to be explained in detail hereinafter with reference to FIG. 1 OB, FIG. 11 and FIG. 12). The block recovery area (if configured and used) is updated as needed during the online data storage process (explained in detail hereinafter with reference to FIG. lOB).
The actual data blocks depicted in FIG 5 (via reference numerals 503-1 thru 503-m), are also updated as needed during the online data storage process.
Reference should now be made to FIG. 6 which, as indicated hereinbefore, depicts an exemplary logical layout for each data block depicted in FIG. S.
2s In particular FIG. 6 depicts block checksum 601; block sequence number 602; record count 603; and actual data records 604-1 thru 604-3.
Block checksum 601 is a check value which may optionally be used (and is used in a ~-lcre.-cd embodiment of the invention) to determine if a block transfer is sllcces~ful.
Block sequence number 602 is sequentially assigned numerical value which may be used to properly insert a recovered block, in the sequence of blocks in a - / CA 0221451C. 1997-09-03 WO 9613J.336 P<_T~T7S96/~S6 ,-~6 -15- -'. , ;;
given file on the mediuln, following a RAM loss condition, as will be explained in greater detail hereinafter with reference to FIG 12.
Record count 603 is a numerical value indicative of the nurnber of records in a given block within a file. For the exarnple depicted in FIG. 6, record count 603 would be set to 3 indicating the presence of the three records illustrated (604-1 thru 604-3) Finally, before turning to the detailed description of the methods contemplated by the invention, with specific reference to FIGS. 7-12, it should be noted that in addition to the data integrity protection techniques contemplated by the invention lo elimin,.tin~ the need to write to the above described (disk resident) control struc~ures after the aforementioned data storage initialization process (explained with reference to FIG. 9) has been completed; another key factor in m~int~ inin~ data integrity, in accordance with the teachings of the invention, is the ability to restart the data storage system (removable medium) following a CPU reset or power down condition.
According to the preferred embodiment of the invention, this restart capability is realized by: (a) maintaining data records in the recording instrument's internal memory (preferably a backed memory such as backed RAM) until the records have been successfully transferred to disk; (b) m,.n;~E~in~ the data storage and disk update processes using a series of atomic "go/no-go" operations to prevent corruption of data blocks; and (c) m~int~ininE a "duplicate" block image on disk for performing the aforementioned (optional) memory loss recovery processing in the event of a RAM loss condition.
According to the preferred embodiment of the invention, the steps listed above (steps (a)-(c)) are employed when implementing the preferred illustrative processes described hereinafter with reference to FIGS. 7-12. Those skilled in the art will recogruze that the sequence of certain steps in the illustrative processes themselves (the processes depicted and described with reference to FIGS. 7-12), may be altered;
that certain of the illustrated process steps may be elimin~.ted (for example, where optional RAM loss condition processing is not practiced)~e~ ;~ ut dcEsr" l;"~ "Athc s~opc or .pirit of tho in~*~tion ~ hich is intcndcd t~ bc limitod only by tho 013 m6 app~nd~d-h~rot~
Ai',~ ,r, S,-IE~r WO gf '3~ 6 PCrlUS96/OS676 Reference should now be made to FIG. 7 which depicts, in accordance with the te~hing~ of one embodiment of the invention, an illu~LIdLivt; set of process steps for form~t~ing the storage medium.
In particular, FIG. 7 depicts the form~ttinp; process as including the 5 following steps: de~r.~ if the m~ m~ is ~r~,~ell~y inserted in the instrument (step 701); ~ g if the micro switch door (door 107 shown in FIG. 1) is closed (step 702); form~tting the medium itself (using, for example, a file m~n~gement utility such as DOS), if the medium is p~ CI ly inserted in the instrument (step 703); and then del~ i-.g if the format operation was p~,iro~ ed succe~fully (step 704). If the results o of any of the aforementioned steps of dt;te ;nil-g is negative, a "Format Failed" report is shown generated at step 705.
The actual step of form~tting the media per se (step 703) prepares the disk for both physical and logical access under the exernplary DOS ~ dLillg system.
During the forrnat process all sectors of the disk are tested for both read and write s access. "Bad" sectors are identified as being bad in the DOS File Allocation Tables (FAT). The DOS Boot Record is also created during format.
According to the invention, the forrniqtting process described with reference to FIG. 7, must be performed prior to the data storage initi~li7~tion process described hereinafter with reference to FIG. 9.
Reference should now be made to FIG. 8 which depicts, in accordance with the te~chin~ of one embodiment of the invention, an illustrative set of process steps for configuring non-volatile memory with a set of storage operation parameters.
The user must configure the parameters under which the storage system will operate. These parameters include (for a typical process data recording system): (a) the type of data to be stored (process data, alarms, events, etc); (b) the data points to be stored; and (c) the rate of storage. Those skilled in the art will realize that this list of parameters is set forth for the sake of illustration only and that a fewer or greater nurnber of parameters may be a~ liate depending on the application in which the recording instrument is being employed.
According to the ~l~;r~llc;d embodirnent of the invention, the configuration information (user setup information) is stored in a non-volatile memory device, such as an EEPROM. As indicated hereinbefore, the term CA 02214~1~ 1997-09-03 W~ 96134336 I''CT/USg6/OS676 "non-volatile memorv" refers (in addition to the exemplary EEPROM), to ROM, PROMand any other type of memory device that m~int~inc its content without power. The setup information is used to partition the disk during the data storage initi~li7~tion process described helei-l~rl~,L with reference to FIG. 9.
The illu~LIdLiv~ process for performing the configuration process described hereinabove may be seen, with reference to FIG. 8, to include steps for ~eeiryil.g the aforementioned application dependent par~m~ters (shown p~lrol..led at steps 801-803 for the specific illu~lldLivti ~,..,.-,t~ iccllcce(1 hereinabove); and storing the specified parameters in non-volatile memory (step 804, with EEPROM being 0 used as an exemplary form of non-volatile memory).
The further step of verifying that storing the specified parameters in non-volatile memory was s~lccç~ful, is shown as step 805 in FIG. 8. In the event that the storage operation does not succee~l, a "EEPROM Failed" report is shown generated at step 806.
Reference should now be made to FIG. 9 which depicts, in accordance with the tç~hingc of one embodiment of the invention, an illustrative set of process steps for initislli7ing the storage metlillm (referred to hereinbefore as p~lrO.~ g data storage initiali_ation).
The primary purpose of initi~li7~tion is to prepare the disk for secure data storage operation. The non-volatile user setup information tells the initi~li7~tion process how to partition the disk.
According to the illustrative embodiment of the invention depicted in FIG. 9, the following actions are performed during initi~li7~tion: read the data storage configuration stored in non-volatile memory (step 901);
~let~rmine the file allocation requirements (step 902) from the configuration data, specifically the number of files needed and file size as specified by the user (or otherwise derived by the data processing device included in the l~coldillg instrument) during setup, and then create the actual files on the disk, including writing file control information to the storage medium (step 903).
The further step of verifying that the write operation was suc cçccful, is shown as step 904 in FIG. 9. In the event that the write operation does not sl~ccee~l, a "INIT Failed" report is shown generated at step 905.
CA 02214~1~ 1997-09-03 WO 96134336 r~ r ~ l 5ti76 FIG. 9 goes on to illustrate steps directed to creating and storing the aforementioned (optional) static header onto the disk.
Where the static header is used, the header inforrn~tion is shown written to disk at step 906; followed by the step of verifying that the write operation pt;,ro~ ed at step 906 was succe~ful (at step 907). Again, an "INIT Failed" report is showngenG.~d (at step 908) if the ~,vrite to disk of the static header was lm~llGces~fill Finally, FIG. 9 goes on to show the step of clearing the data area within the files (step 909) as an added ~ r.,.,~d step (not l-~cess~. y in all embo(1im~nte of the invention) to insure file integrity. For example, the step of clearing could be p~,r~"",ed o by writing all zeros to the file space. An "INIT Failed" report is also generated (step 91 1 ) if the clearing operation (when employed) is unsuccessful.
Once again, according to the invention, disk space allocation is performed during the above described initi~li7~tion process only. This means that no further write-access the various illustrative control structure discussed hereinabove (the Boot Record, FAT, Root Directory, or Static Header) will be performed for this disk.
Also, no data blocks are written to the disk until the initialization process is complete.
Reference should now be made to FIG. 1 OA and FIG. 1 OB which depict, in accordance with the te~~hinp~ of the invention, an illustrative set of process steps for ~n~n~gin~ the data transfer process contemplated by theinvention.
As indicated hereinabove, the recording instrument contemplated by the invention m~int~in~ a series of data block structures in RAM memory (preferably backed RAM) that are used to stage the data records prior to their storage on disk. Each data block structure contains an exact image of a data block on the disk. The size of each Data Block is preferably selected to match the allocation unit of the disk (512 bytes for a 1.44 Mbyte floppy disk or a 512K memory card). This would tend minimi~ loss of data if corruption occurs.
In order to prevent the corruption of the data block structures in RAM, and to provide a secure transfer of the data record to the disk (and be able to detect the corruption of data block structures transferred to disk), the following proce~ing and fee-lb~l k sequence (depicted in FIG. lOA and continued in FIG. lOB) may be used:
determine if there exists any process data received and/or derived by the instrument CA 02214~1~ 1997-09-03 WO 96134336 PCT/U~ SC76 waiting to be stored in the RA~ (shown as step 1001 in FIG. lOA); build data records from any process data waiting to be stored (step 1002); write a record created at step 1002 to a predefined RAM data block (step 1003); keep track of the number of records built and stored by, for example, incremçntin~ a record count to officially add the record S the data block (step 1004); assign a block sequence number, preferably calculate the aforementioned block checksum (described hereinbefore with reference to FIG. 6), and store both of these values in the block (step 1005); mark each block that is ready for transfer to the medium with an indication that it is ready for l~ sr.,. (step 1006), by for example setting a flag associated with the block stored in RAM; cletçrrnin~?, whenever 10 the removable medium is to be periodically up-l~te-l (an option; not a requirement to practice the inveNtion), if it is time for the periodic update (step 1007); deterrnine if there are blocks in RAM waiting to be L~ r~ d (step 1008); fletermine whether or not the removable medium is l~lu~ ly inserted in the instrument, i.e., for the a~.~dlus depicted in FIG. 1 and FIG. 2, clet~rmine if the micro switch door closed with the 15 removable medium properly inserted therein (step 1009); write a data block awaiting transfer to the removable storage medium (step 1010) if the removable media is properly inserted in the instrument; determine if the write operation was s-lcccs~ful (step 1011), by, for example, reading the aforementioned check sum value (if created and stored in the data block), and mark the data block in RAM as "Transfer Completed" to 20 indicate the transfer was complete whenever it is cletçrmined by step 1011 that the write operation to disk was successful (step 1012).
With respect to performing step 1010 in FIG. 1 OB (the step of write a data block awaiting transfer to the removable storage medium), what is implied, although not specifically shown in FIG. 1 OB, is that the write is to two places in a given 2s file when the aforementioned block recovery option is used; namely to the block recovery area first and then the given data block itself.
By lltili7ing the ~lcre..ed process depicted in FIG. lOA and FIG. lOB, m~rking the block in RAM as "Transfer Completed" (step 1012), completes the fee~lb~k path required to deterrnine a sllçce~ful write to disk has occurred.
If the write fails, the block will remain marked as awaiting transfer, and will be m~int~ined in the intern~l RAM (preferably backed RAM), until the next update _ CA 02214~1~ 1997-09-03 WO 9~'3 1~36 PCTIUS96/OS676 cycle or asynchronous attempt (depending on application) is made to write to disk agam.
When cyclic updating of disk is performed, the cycle will be repeated at periodic intervals until the block has been sllccçc~fully transferred to disk, at which 5 point in time the block will have been marked as "Transfer Completed". After a block is m~rketl as "Transfer Completed" it may be cleared and recycled as needed. Those skilled in the art will readily appreciate that the periodic update option is useful in preserving the life of certain types of removable storage media (e.g., a floppy disk).
As indicated hereinabove, if the memory loss recovery option is used, lo each data block will be written to the disk file twice: once to the normal data area, and once to the special block recovery area. The duplicate block will be used to restore the corresponding block in the data area in the event that RAM is lost during a power-down, as will be explained in greater detail hereinafter with reference to FIG. 12.
Reference should now be made to FIG. 11 which depicts, in accordance I s with the te~l~hing~ of one embodiment of the invention, an illustrative set of process steps for recovering from a power loss condition.
According to the ~cr~ ;d embodiment of the invention, all untransferred blocks in the RAM area upon a restart (blocks marked as awaiting transfer) are located and then writes to disk are attempted for each such block. This 20 resumes the feedback process described hereinbefore. If a data block on disk had been corrupted because of a power down, this process will restore it by ovc. ~vfili"g it with the RAM-resident copy.
More particularly, with reference to FIG. 1 1, an exemplary set of process steps contemplated by the invention to perform the aforestated functions include:
25 det~rmininE, after a power loss condition, if the non-volatile memory was previously configured (step 1 101 ); det~nnining if there are any data blocks that are marked as awaiting transfer to the removable medium (step 1102); cletennining if said medium is properly inserted in said instrument, i.e., inserted in the ,~co.di,lg instrument with door 107 closed when using an instrument of the type depicted in FIG. 1 (step 1 103); writing 30 a block awaiting transfer to a target file on the medium to the recovery area of the target file, if the optional recovery area rli~c~-~se-l hereinbefore (shown at 502 in FIG. 5) is used (step 1 104); writin~ a block awaiting transfer to a target file on the medium, to the CA 022l4~l~ l997-09-03 WO9~'3~ 6 PCI/US96/OS676 data storage portion (shown, for example, at 503-1 in FIG. 5) of the target file (step 1105); .1~ if the write operations ~,.ro-l--ed in step 1104 (if ~ ro----ed) and step 1105 were sllcces~ful (step 1106); mslrkinp each data block s~lcces~fillly transferred to the medium to indicate the transfer was complete whenever it is ~ l in step s 1106 that the write operation(s) was (were) ~llcces~ful (step 1107); and ~l~l. ...;..;..~ if all blocks have been PY~mined subsequent to experiencing a given loss of power condition (step 1108).
R~r~.~..ce should now be made to FIG. 12 which depicts, in accordance with the t~rllin~s of one embodiment of the invention, a set of exemplary process steps o for recovering from a RAM loss condition, as defined hereinbefore.
If the capacitor-backed RAM (or RAM which is not backed) has been lost, the ex~mpl~ry memory loss recovery process set forth htl~i-.arL~l can be used to attempt to restore and/or repair a corrupted data block on disk.
The process involves the following steps which are ill~letr~te(l in FIG. 12:
det~rminin~, after a RAM[ loss condition has occurred, if the non-volatile memory was previously configured and the security micro switch is closed (step 1201); if so, finding the logical last data block in each disk file (step 1202) to determine if corruption has occurred (step 1203) by, for example, testing the block checksum value; and (if corruption has occurred), the contents of the "duplicate" block in the aforementioned recovery area (if this option is used), should be copied into the logical last data block, ovel ~vliLil1g the corrupted contents of the logical last data block (step 1204).
Not shown in FIG. 12, since it con~ uLes an ~ltPrn~te embodiment of the invention, the co-- ~ed logical last data block could be "repaired" if no copy were m~int~ined in the recovery area. A block could be ",e~ai.ed", for example, by assigning 2s the next logical sequence number to the block being repaired; setting its record count to zero; calculating a block checksum value; and then rewriting the "repaired" block to disk.
The illustrative process depicted in FIG. 12 continues with steps 1205-1209 only if (1) the block recovery area option is used; and (2) a dçtermin~tion at step 1203 is made that a given data block is not colTupted. In particular, steps 1205-1209 involve: dçterminin~ if the data block written in the recovery area (now assumed to be used) for the file is newer than the logical last block (step 1205); determinin~, whenever WO 96/34336 ,~ J~6/0~;'6 . ., it is deterrnined at step 1205 that the data block written in the recovery area for the file is newer than the logical last block, if the sequence nurnber for the data block written in the recovery area equals the sequence number for the logical last data block (step 1206);
copying the data block written in the recovery area for the file into the last logical data s block whenever it is deterrnined in step 1206 that the sequence nurnber for the data block written in the recovery area equals the sequence nurnber for the logical last data block (step 1207); deterrnining, whenever it is deterrnined in step 1206 that the sequence number for the data block written in the recovery area does not equal the sequence nurnber for the logical last data block, if the sequence nurnber for 10 the data block written in the recovery area is greater than the sequence nurnber for said logical last data block (step 1208); and adding the data block written in the recovery area at the logical end of the given file whenever it is deterrnined at step 1208 that the sequence nurnber for the data block written in the recovery area is greater than the sequence nurnber for the logical last data block (step 1209).
The process depicted in FlG. 12 concludes with step 1210, which follows the performance of any of steps 1204, 1207, 1208 or 1209 (arrived at based on Ihe results of the various deterrninations made at steps 1203, 1205, 1206 and 1208 shown in FIG. 12), which causes the process depicted in FIG. 12 to be iterated when files remain 20 to be examined (after a given pass through the FIG. 12 process), following the occurrence of a RAM loss condition.
What has been described in detail hereinabove are methods and apparatus which meet all of the aforestated objectives. As previously indicated, those skilled in the art will recognize that the foregoing description has been presented for the sake of 25 illustration and description only. ¦Tt S ~IOt intehdcd to bc oxh~ti~o ar to li...i~ tho invf~r.~;~ .h,. pr~ r '-;'cc~ tcb~ o~ mnnyrr.odi~l~6~noond Vz~7.~ ti~ 7r~ r~cc~;~1~ ;r 1~~ r ~ bo~ ~hir~
For example, the aforementioned teaching for protecting the integrity of process data transferred to and stored on a removable 30 storage media, associated with a programmable stand alone data recording instrument, may be applied to protect the integrity of process data transferred to and stored on fixed storage media (installed or external) associated with such instruments.
,rl WO 9o'/3433~6 rCI'/U~:;95/05~'7O .
' ! -23- ' ,''' ~' The embodiments and examples set forth herein were presented in order to best explain the principles of the instant invention and its practical application to thereby enable others skilled in the art to best utilize the instant invention in various embodiments and with various modifications as are suited to the particular use 5 contemplated.
~ LI vi ~i of thc ~1~0V~ , bc undcr~too=~
appended hereto are intended to cover all such m~iD~ariations which fall within the true scope = ,~
Claims (26)
1. A method for protecting the integrity of process data stored on a removable storage media (201) associated with a programmable stand alone data recording instrument(100, 200) that includes a Random Access Memory (RAM) (103) and non-volatile memory (104), comprising the steps of:
(a) formatting said removable storage media;
(b) configuring a set of storage parameters used to partition said media, wherein said step of configuring includes the steps of specifying said parameters and storing the specified parameters in non-volatile memory (104);
(c) initializing said storage media for secure data storage operation by partitioning said media into a set of files utilizing the set of storage parameters stored in non-volatile memory;
(d) generating a signal indicative of whether or not said medium is properly inserted in said instrument; and (e) managing process data received and/or derived by said instrument and the transfer of said data to said media, wherein said step of managing includes the steps of:
(e1) building and storing data records in predefined RAM data blocks utilizing said data;
(e2) keeping track of the number of records built and stored;
(e3) marking each block that is ready for transfer to said medium;
(e4) determining, in response to said signal indicative of whether or not said medium is properly inserted in said instrument, if said media is properly inserted therein;
(e5) writing to a file on said medium one of the blocks awaiting transfer thereto after it is determined in step (e4) that the removable media is properly inserted in said instrument;
(e6) determining if the write operation was successful; and (e7) marking the data block in RAM to indicate the transfer was complete whenever it is determined in step (e6) that the write operation was successful.
(a) formatting said removable storage media;
(b) configuring a set of storage parameters used to partition said media, wherein said step of configuring includes the steps of specifying said parameters and storing the specified parameters in non-volatile memory (104);
(c) initializing said storage media for secure data storage operation by partitioning said media into a set of files utilizing the set of storage parameters stored in non-volatile memory;
(d) generating a signal indicative of whether or not said medium is properly inserted in said instrument; and (e) managing process data received and/or derived by said instrument and the transfer of said data to said media, wherein said step of managing includes the steps of:
(e1) building and storing data records in predefined RAM data blocks utilizing said data;
(e2) keeping track of the number of records built and stored;
(e3) marking each block that is ready for transfer to said medium;
(e4) determining, in response to said signal indicative of whether or not said medium is properly inserted in said instrument, if said media is properly inserted therein;
(e5) writing to a file on said medium one of the blocks awaiting transfer thereto after it is determined in step (e4) that the removable media is properly inserted in said instrument;
(e6) determining if the write operation was successful; and (e7) marking the data block in RAM to indicate the transfer was complete whenever it is determined in step (e6) that the write operation was successful.
2. A method according to Claim 1 characterised in that said step of initializing further comprises the step of performing a one time allocation of file space on said medium to thereby protect media file control structures from being corrupted.
3. A method according to Claim 1 or 2 characterised in that said step of managing further comprises the step of organizing process data within a given file into independent blocks.
4. A method according to Claim 3 characterised in that said independent blocks are sequenced.
5. A method according to Claim 3 or 4 characterised in that said independent blocks are checksummed to enable the presence of corruption to be detected after a data transfer operation is complete.
6. A method according to any preceding Claim characterised in that said step of formatting further comprises the steps of:
(a) determining if said medium is properly inserted in said instrument;
(b) utilizing a file management utility to format the medium if properly inserted in said instrument;
and (c) verifying that the format operation performed under said utility was successful.
(a) determining if said medium is properly inserted in said instrument;
(b) utilizing a file management utility to format the medium if properly inserted in said instrument;
and (c) verifying that the format operation performed under said utility was successful.
7. A method according to any preceding Claim characterised in that said step of configuring and said step of specifying included therein, further comprises the steps of:
(a) selecting the type of data to be stored;
(b) selecting the data points to be stored; and (c) selecting the data storage rate.
(a) selecting the type of data to be stored;
(b) selecting the data points to be stored; and (c) selecting the data storage rate.
8. A method according to any preceding Claim characterised in that said step of configuring further comprises the step of verifying that said step of storing the specified parameters in non-volatile memory was successful.
9. A method according to any of claims 2 to 8 characterised in that said step ofperforming a one time allocation of file space on said medium, further comprises the steps of:
(a) reading said specified parameters stored in non-volatile memory;
(b) determining file allocation requirements utilizing said specified parameters;
(c) writing file control information to said media;
and (d) determining if the step of writing file control information to said media was successful.
(a) reading said specified parameters stored in non-volatile memory;
(b) determining file allocation requirements utilizing said specified parameters;
(c) writing file control information to said media;
and (d) determining if the step of writing file control information to said media was successful.
10. A method according to Claim 9 characterised by further comprising the steps of:
(a) writing application header information to said media for each file created; and (b) determining if the step of writing application header information to said media for each file created was successful.
(a) writing application header information to said media for each file created; and (b) determining if the step of writing application header information to said media for each file created was successful.
11. A method according to Claim 9 or 10 characterised by the steps of clearing the data area within each file on said medium and determining if said clearing step was successful.
12. A method according to any preceding Claim characterised in that said step ofmanaging further comprises the step of determining if process data received and/or derived by said instrument is waiting to be stored.
13. A method according to any preceding Claim characterised in that said step ofmanaging further comprises the step of periodically determining if any block is awaiting transfer to said medium.
14. A method according to any preceding Claim characterised in that said step ofmanaging further comprises the step of providing each block that is ready for transfer to said medium with a check value which may be used to determine if a block transfer is successful.
15. A method according to any preceding Claim characterised in that said step ofmanaging further comprises the step of providing each block that is ready for transfer to said medium with a sequence number to enable a recovered block to be properly inserted in the sequence of blocks in the file on said medium in the event of a RAM loss condition.
16. A method according to Claim 14 characterised in that said step of writing to said medium further comprises the steps of first writing a block awaiting transfer to said medium to a recovery area in a given file located thereon and then writing the same data block to a data storage portion of said file.
17. A method according to any preceding Claim characterised by the steps of:
(a) determining, after a power loss condition, if said non-volatile memory was previously configured;
(b) determining if there are any data blocks that are marked as awaiting transfer to said medium;
(c) determining if said medium is properly inserted in said instrument;
(d) writing a block awaiting transfer to a target file on said medium to the recovery area of said target file;
(e) writing a block awaiting transfer to a target file on said medium to the data storage portion of said target file;
(f) determining if the write operations performed in steps (d) and (e) were successful; and (g) marking each data block successfully transferred to said medium to indicate the transfer was complete whenever it is determined in step (f) that the write operations were successful.
(a) determining, after a power loss condition, if said non-volatile memory was previously configured;
(b) determining if there are any data blocks that are marked as awaiting transfer to said medium;
(c) determining if said medium is properly inserted in said instrument;
(d) writing a block awaiting transfer to a target file on said medium to the recovery area of said target file;
(e) writing a block awaiting transfer to a target file on said medium to the data storage portion of said target file;
(f) determining if the write operations performed in steps (d) and (e) were successful; and (g) marking each data block successfully transferred to said medium to indicate the transfer was complete whenever it is determined in step (f) that the write operations were successful.
18. A method according to Claim 17 characterised by the step of determining if all blocks have been examined subsequent to experiencing a given loss of power condition.
19. A method according to any preceding Claim characterised by:
(a) determining, after a power loss condition, if said non-volatile memory was previously configured;
(b) determining if there are any data blocks that are marked as awaiting transfer to said medium;
(c) determining if said medium is properly inserted in said instrument;
(d) writing a block awaiting transfer to a target file on said medium to said target file;
(e) determining if the write operation performed in step (d) was successful; and (f) marking each data block successfully transferred to said medium to indicate the transfer was complete whenever it is determined in step (e) that the write operation was successful.
(a) determining, after a power loss condition, if said non-volatile memory was previously configured;
(b) determining if there are any data blocks that are marked as awaiting transfer to said medium;
(c) determining if said medium is properly inserted in said instrument;
(d) writing a block awaiting transfer to a target file on said medium to said target file;
(e) determining if the write operation performed in step (d) was successful; and (f) marking each data block successfully transferred to said medium to indicate the transfer was complete whenever it is determined in step (e) that the write operation was successful.
20. A method according to any preceding Claim characterised by the steps of:
(a) determining, after a RAM loss condition, if said non-volatile memory was previously configured and if said medium is properly inserted in said instrument;
(b) locating the last logical data block in each data file on said medium;
(c) determining if the last logical data block located in a given data file is corrupted;
(d) copying the data block written in said recovery area for said file into said last logical data block whenever it is determined in step (c) that said given data block was corrupted;
(e) determining, whenever said given data block is not corrupted, if the data block written in said recovery area for said file is newer than said logical last block;
(f) determining, whenever it is determined at step (e) that the data block written in said recovery area for said file is newer than said logical last block, if the sequence number for the data block written in said recovery area equals the sequence number for said logical last data block;
(g) copying the data block written in said recovery area for said file into said last logical data block whenever it is determined in step (f) that the sequence number for the data block written in said recovery area equals the sequence number for said logical last data block;
(h) determining, whenever it is determined in step (f) that the sequence number for the data block written in said recovery area does not equal the sequence number for said logical last data block, if the sequence number for the data block written in said recovery area is greater than the sequence number for said logical last data block; and (i) adding the data block written in said recovery area at the logical end of said given file whenever it is determined at step (h) that the sequence number for the data block written in said recovery area is greater than the sequence number for said logical last data block.
(a) determining, after a RAM loss condition, if said non-volatile memory was previously configured and if said medium is properly inserted in said instrument;
(b) locating the last logical data block in each data file on said medium;
(c) determining if the last logical data block located in a given data file is corrupted;
(d) copying the data block written in said recovery area for said file into said last logical data block whenever it is determined in step (c) that said given data block was corrupted;
(e) determining, whenever said given data block is not corrupted, if the data block written in said recovery area for said file is newer than said logical last block;
(f) determining, whenever it is determined at step (e) that the data block written in said recovery area for said file is newer than said logical last block, if the sequence number for the data block written in said recovery area equals the sequence number for said logical last data block;
(g) copying the data block written in said recovery area for said file into said last logical data block whenever it is determined in step (f) that the sequence number for the data block written in said recovery area equals the sequence number for said logical last data block;
(h) determining, whenever it is determined in step (f) that the sequence number for the data block written in said recovery area does not equal the sequence number for said logical last data block, if the sequence number for the data block written in said recovery area is greater than the sequence number for said logical last data block; and (i) adding the data block written in said recovery area at the logical end of said given file whenever it is determined at step (h) that the sequence number for the data block written in said recovery area is greater than the sequence number for said logical last data block.
21. A method according to any preceding Claim characterised by a step of managing comprises the step of providing each block that is ready for transfer to said medium with a sequence number to enable a repaired block to be properly inserted in the sequence of blocks in the file on said medium in the event of a RAM loss condition.
22. A method according to Claim 21 further comprising the steps of:
(a) determining, after a RAM loss condition, if said non-volatile memory was previously configured;
(b) locating the last logical data block in each data file on said medium;
(c) determining if the last logical data block located in a given data file is corrupted; and (d) repairing said last logical data block whenever it is determined in step (c) that said given data block was corrupted.
(a) determining, after a RAM loss condition, if said non-volatile memory was previously configured;
(b) locating the last logical data block in each data file on said medium;
(c) determining if the last logical data block located in a given data file is corrupted; and (d) repairing said last logical data block whenever it is determined in step (c) that said given data block was corrupted.
23. A method for protecting the integrity of process data stored on a removable storage media associated with a programmable stand alone data recording instrument (100,200) that includes a Random Access Memory (RAM) and non-volatile memory, comprising the steps of:
(a) formatting said removable storage media;
(b) configuring a set of storage parameters used to partition said media, wherein said step of configuring includes the steps of specifying said parameters and storing the specified parameters in non-volatile memory;
(c) initializing said storage media for secure data storage operation by partitioning said media into a set of files utilizing the set of storage parameters stored in non-volatile memory; and (d) managing process data received and/or derived by said instrument and the transfer of said data to said media, wherein said step of managing includes the steps of:
(d1) building and storing data records in predefined RAM data blocks utilizing said data;
(d2) keeping track of the number of records built and stored;
(d3) marking each block that is ready for transfer to said medium;
(d4) writing to a file on said medium one of the blocks awaiting transfer thereto;
(d5) determining if the write operation was successful; and (d6) marking the data block in RAM to indicate the transfer was complete whenever it is determined in step (d5) that the write operation was successful.
(a) formatting said removable storage media;
(b) configuring a set of storage parameters used to partition said media, wherein said step of configuring includes the steps of specifying said parameters and storing the specified parameters in non-volatile memory;
(c) initializing said storage media for secure data storage operation by partitioning said media into a set of files utilizing the set of storage parameters stored in non-volatile memory; and (d) managing process data received and/or derived by said instrument and the transfer of said data to said media, wherein said step of managing includes the steps of:
(d1) building and storing data records in predefined RAM data blocks utilizing said data;
(d2) keeping track of the number of records built and stored;
(d3) marking each block that is ready for transfer to said medium;
(d4) writing to a file on said medium one of the blocks awaiting transfer thereto;
(d5) determining if the write operation was successful; and (d6) marking the data block in RAM to indicate the transfer was complete whenever it is determined in step (d5) that the write operation was successful.
24. Apparatus for protecting the integrity of process data stored on a removable storage media associated with a programmable stand alone data recording instrument ( 100, 200), comprising:
(a) programmable data processing means (101);
(b) Input/Output means (102), coupled to said programmable data processing means, for receiving unformatted process data input to said instrument;
(c) memory means (103), coupled to said programmable data processing means, for temporarily storing unformatted process data received and/or derived by said instrument;
(d) non-volatile memory (104), coupled to said programmable data processing means (105), for storing a set of removable media configuration parameters;
(e) media interface means, coupled to said programmable data processing means, for receiving said removable storage medium when properly inserted therein and making said storage medium available to said programmable data processing means for data transfer operations; and (f) means (106) to generate a signal to indicative of whether or not said mediumis properly inserted in said instrument.
(a) programmable data processing means (101);
(b) Input/Output means (102), coupled to said programmable data processing means, for receiving unformatted process data input to said instrument;
(c) memory means (103), coupled to said programmable data processing means, for temporarily storing unformatted process data received and/or derived by said instrument;
(d) non-volatile memory (104), coupled to said programmable data processing means (105), for storing a set of removable media configuration parameters;
(e) media interface means, coupled to said programmable data processing means, for receiving said removable storage medium when properly inserted therein and making said storage medium available to said programmable data processing means for data transfer operations; and (f) means (106) to generate a signal to indicative of whether or not said mediumis properly inserted in said instrument.
25. Apparatus according to Claim 24 characterised in that said removable storagemedia is a floppy disk.
26. Apparatus according to Claim 24 characterised in that said removable storage media is a PCMCIA card.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/429,281 US5734894A (en) | 1995-04-25 | 1995-04-25 | Methods and apparatus for protecting the integrity of process data stored on a removable storage medium |
| US08/429,281 | 1995-04-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2214515A1 true CA2214515A1 (en) | 1996-10-31 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002214515A Abandoned CA2214515A1 (en) | 1995-04-25 | 1996-04-23 | Methods and apparatus for protecting the integrity of process data stored on a removable storage medium |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US5734894A (en) |
| EP (1) | EP0823086B1 (en) |
| JP (1) | JPH11514463A (en) |
| AU (1) | AU713778B2 (en) |
| CA (1) | CA2214515A1 (en) |
| DE (1) | DE69608797T2 (en) |
| WO (1) | WO1996034336A1 (en) |
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| ATE210854T1 (en) * | 1999-04-10 | 2001-12-15 | Basis Gmbh Edv Vertriebs Ges | DATA CARRIER WITH RECOVERABLE BASE DATA BASE AND METHOD FOR PRODUCING SAME |
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-
1995
- 1995-04-25 US US08/429,281 patent/US5734894A/en not_active Expired - Lifetime
-
1996
- 1996-04-23 AU AU55701/96A patent/AU713778B2/en not_active Ceased
- 1996-04-23 WO PCT/US1996/005676 patent/WO1996034336A1/en active IP Right Grant
- 1996-04-23 JP JP8532652A patent/JPH11514463A/en active Pending
- 1996-04-23 DE DE69608797T patent/DE69608797T2/en not_active Expired - Lifetime
- 1996-04-23 EP EP96913085A patent/EP0823086B1/en not_active Expired - Lifetime
- 1996-04-23 CA CA002214515A patent/CA2214515A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US5734894A (en) | 1998-03-31 |
| AU5570196A (en) | 1996-11-18 |
| DE69608797T2 (en) | 2000-11-23 |
| DE69608797D1 (en) | 2000-07-13 |
| EP0823086B1 (en) | 2000-06-07 |
| JPH11514463A (en) | 1999-12-07 |
| AU713778B2 (en) | 1999-12-09 |
| WO1996034336A1 (en) | 1996-10-31 |
| EP0823086A1 (en) | 1998-02-11 |
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