to call the error checking subroutine given earlier
in
this chapter. If the four listed were the
only files beginning with
"T",
you will see:
01
,FILES SCRATCHED,04,00
READY.
The
"04"
tells you 4 files were scratched.
MORE ABOUT SCRATCH
SCRATCH is a powerful command and should be used with caution
to
be sure you
delete only the files you really want erased. When using
it
with a pattern,
we
suggest you
first use the same pattern
in
a DIRECTORY command, to be sure exactly which files will
be deleted. That way you'll have no unpleasant surprises when you use the same pattern
in
the SCRATCH command.
Recovering from a SCRATCH
If
you accidentally SCRATCH a
file
you shouldn't have, there
is
still a chance of
saving it. Like BASIC's NEW command, SCRATCH doesn't really wipe out a
file
itself;
it merely clears the pointers to
it
in
the diskette directory. There may be an "Unscratch"
program on your Test/Demo diskette.
NOTE:
If you accidentally SCRATCH a
file
within the DOS Shell (see Chapter 4),
you can unscratch it with the Shell's RESTORE FILES function.
More about Splats
Never scratch a splat file. These are files that show up
in
a directory listing with an
asterisk
(*) just before the
file
type for an entry. The asterisk (or splat) means that
file
was
never properly closed, and thus there
is
no valid chain
of
sector links for the Scratch
command to follow
in
erasing the file.
If you SCRATCH such a file, odds are you will improperly free up sectors that are
still needed by other programs or files and cause permanent damage to those later when
you add more files to the diskette.
If
you
find
a splat file, or if you discover too late that
you have scratched such a file, immediately validate the diskette using the VALIDATE
command described later
in
this chapter. If you have added any files to the diskette since
scratching the splat file, it
is
best to immediately copy the entire diskette onto another
fresh diskette, but do this with a copy program rather than with a backup program.
Otherwise, the same problem will be recreated on the new diskette. When the new copy is
done, compare the number
of
blocks free
in
its directory to the number free on the original
diskette. If the numbers match, no damage has been done. If not, very likely at least one
file on the diskette has been corrupted, and all should be checked immediately.
19
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