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0
 FIDDLE
0
0The FIDDLE program may be used to set or reset bits in a
0bitmap within a disk file.  It's uses include freeing
0corrupted file headers found by the VFY utility.
0
0Command format
+_______ ______
0
0>FID
FID>file-spec [/switches]
0BIT? bit
0  .
0  .
0  .
0BIT?
0where
0
0
0file-spec      is the file specifier of the file containing
0               the bit map.  The file must be on a mounted
0               FILES-11 volume and should not be accessed by
0               another user.
0
0/switches      are an optional set of switches describing
0               the position of the bitmap in the file and
0               whether bits are to be set or cleared.  They
0               may be any of the following:
0
0
0
0
0
0
                                                       PAGE 2
0
 /SET           Set the bit.  The bits specified by the user
0               are to be set.  If they are already set an
0               error message is generated.  The converse of
0               /SE is to clear the specified bits which must
0               initially be set.
0
0               Default: /-SE
0
0/ADJUST:value  Adjust the bit position by adding "value" to
0               it.  A value of -1 could be used to operate
0               on a bit string whose first bit is bit 1.
0
0               Default: /AD:O
0
0/BYTE:byte     Specifies that the bitmap starts at byte
0               "byte" within a block.  This could be used if
0               there was some header information at the
0               start of the bit string.
0
0               Default: /BY:O
0
0/BLOCK:block   Specifies the starting virtual block number
0               of the bitmap within the file.  This could be
0               used if the bitmap started with the second or
0               subsequent block in the file.
0
0               Default: /BL:1
0
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0
                                                       PAGE 3
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0
 Example
+_______
0
0A typical use of FIDDLE is to partially mechanize the
0procedure for removing corrupt headers described in the
0November l976 software dispatch.  As an example , suppose
0verify reported file header "1264,0" was bad.  The following
0procedure could be used to free the header:
0
0>DMO SY:
0>MOU SY:/UNL
0>RUN FIDDLE
0FID>[0,0]INDEXF.SYS/AD:-1/BL:3
0BIT?1264
0BIT? ^Z
0
0The bit specifying file header 1264 is reset thereby freeing
0the header.  Note that VFY should be run again to verify
0that only bad headers were freed.
0
0Error Message
+_____ _______
0
0FID -- CANNOT GET COMMAND LINE
0FIDDLE could not read the command line.  Correct the problem
0and re-try the command.
0
0FID -- ILLEGAL SYNTAX : command
0
0
0
0
0
                                                       PAGE 4
0
 The command was not syntactically valid.  Correct the
0problem and re-enter the command.
0
0FID -- INVALID FILE SPECIFIER : command
0The file specifier is invalid.  Quite likely, an invalid
0switch or argument was used.  Correct the problem and re-try
0the command.
0
0FID -- CANNOT OPEN FILE : reason
0The file could not be opened for the specified reason.  The
0file name was probably entered incorrectly.  Correct the
0problem and re-enter the command.
0
0FID -- INVALID INPUT
0The line just typed contained a non-octal character.  FIDDLE
0re-prompts the user for another bit number.  Re-enter the
0bit number correctly.
0
0FID -- ERROR READING FILE : reason
0The file could not be read for the specified reason.  If an
0end of file was detected, the bit number entered was
0probably too big.  Correct the problem and re-enter the
0number.
0
0FID -- ALREADY SET
0The /SE switch was specified and FIDDLE discovered that the
0specified bit was already set.  The bit number was probably
0
0
0
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0
                                                       PAGE 5
0
 entered incorrectly.  Correct the problem and re-enter the
0bit number.
0
0FID -- ALREADY RESET
0The /SE switch was not specified and FIDDLE discovered that
0the bit was already clear.  The bit number was probably
0specified incorrectly.  Correct the problem and re-enter the
0number.
0
0FID -- ERROR WRITING FILE : reason
0The updated block of the bitmap file could not be written to
0the disk for the specified reason.  Correct the problem and
0re-enter the number.
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