DISKCOMP(DOS) UNIX System V DISKCOMP(DOS)
Name
diskcomp - compares the contents of the disk in the source
drive to the disk in the target drive
Syntax
diskcomp [drive:] [drive:] [/l] [/8]
Description
The first drive: option specifies the drive that contains
the source disk, and the second drive: option specifies the
drive that contains the target disk.
If you specify only one drive, diskcomp uses the default
drive as the target drive. If you specify the same drive as
the source and target, diskcomp does a comparison using one
drive, and prompts you to insert the disks as appropriate.
The switches are:
/l Causes diskcomp to compare just the first side of the
disk, even if the disks and drives that you are using
are double-sided.
/8 Causes diskcomp to compare just the first 8 sectors per
track, even if the disks contain 9 or 15 sectors per
track.
diskcomp performs a track-by-track comparison of the disks.
It automatically determines the number of sides and sectors
per track based on the format of the source disk. If the
target disk is not the same type as the disk in the source
drive, diskcomp displays the following message:
Drive types or diskette types not compatible
If all the tracks are the same, diskcomp displays the
message:
Compare OK
If the tracks are not the same, diskcomp displays a
``Compare error'' message that includes the track and side
number where it found the mismatch.
When diskcomp completes the comparison, it prompts you with
the following message:
Compare another diskette (Y/N)?_
If you enter y, diskcomp prompts you to insert the proper
disks and does the next comparison. If you enter n,
diskcomp ends. If the disk in the default drive does not
contain MS-DOS and you end diskcomp, you'll receive the
following message:
Insert disk with COMMAND.COM in drive A
and strike any key when ready
diskcomp does not work on network drives, and you cannot use
it with assigned, joined, or substituted drives. If you
attempt to use diskcomp with these types of drives, it
displays an error message.
diskcomp exit codes
When correctly written programs exit back to MS-DOS, they
return an exit code: 0 if no error occurred, or a value
greater than zero if there was a problem. This exit code
can be tested in batch files, and it allows batch
programmers to ``branch'' to an error-handling routine in
the batch file.
The diskcomp command returns the following exit codes:
0 Compared OK The disks compared exactly.
1 Did not compare The disks were not the same.
2 CONTROL-C error The user terminated with <CTL>c.
3 Hard error An unrecoverable read or write
error occurred - did not
compare.
4 Initialization error There is not enough memory -
invalid drives or command line
syntax.
You can use the batch processing if command to perform error
processing based on the errorlevel returned by diskcomp.
Example
If you want to compare two disks, but your computer has only
one floppy disk drive, drive A, you can simply enter the
following command:
diskcomp a:
MS-DOS prompts you to insert both disks, as required.
Notes
When comparing a disk with a backup disk that you made with
the copy command, you may receive the ``Compare error''
message, even if the files on the disks are identical. This
is because the copy command duplicates the information, but
doesn't necessarily place it in the same location on the
target disk.
diskcomp is an external command.
DISKCOMP(DOS) (printed 8/16/89) DISKCOMP(DOS)