Verify - Commodore 1551 User Manual

The alternate command is:
SA VE "@drive #:Iile name" ,device#
where all the parameters are as usual except for adding a leading "at" sign
(((il).
In this
case, the drive# is required in the alternate command.
The actual procedure is this-the new version is saved completely, then the old
version is scratched, and its directory entry altered to point to the new version. Because it
works this way, there is little if any danger that a disaster such as having the power going
off midway through the process would destroy both the old and new copies of the file.
Nothing happens to the old copy until after the new copy is saved properly.
However, we do offer one caution--do not use @Save on an almost-full diskette.
Only use it when you have enough room on the diskette to hold a second complete copy of
the program being replaced. Due to the way ((i:Save works, both the old and new versions
of the file are on disk simultaneously at one point, as a way of safeguarding against loss of
the program. If there is not enough room left on diskette to hold that second copy, only as
much of the new version will be saved on the 1551 as there is still room for. After the
command completes, a look at a directory will show the new version is present, but
doesn't occupy enough blocks to match the copy in memory.
VERIFY
. This command makes a byte-by-byte comparison of the program currently in mem-
ory against a program on disk. This comparison includes .Iine links, which may be
different for different types of memory configurations. What this means is that a program
saved to disk on a Commodore 64 and re-Ioaded into a Plus4 wouldn't verify properly
because the line links point to different memory locations. If the disk copy of the program
differs at all from the copy in memory, a "VERIFY ERROR" will be displayed. This in
itself doesn't mean either copy is bad, but if they were supposed to be identical, one or the
other has a problem.
FORMAT FOR THE VERIFY COMMAND
VERIFY "file name" ,device# ,relocate flag
where' 'file name" is any string expression, with or without pattern-matching characters,
and "device#" is required and, of course, is normally 8. The relocate flag is optional. If
it is present and is 1, the file will be verified at the memory location where originally
saved. If it is 0, DOS begins verifying at the start of BASIC.
The following version of the command verifies a ftle that was just saved:
VERIFY
"*,,
,device#
The device# is again required.
This command won't work properly after SAVE-WITH-REPLACE, however, be-
cause the last file used was the one deleted, and the drive will try to compare the deleted
file to the program in memory. No harm will result, but "VERIFY ERROR" will always
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