Commodore 1541-II - Validating the Diskette

NOTE: Dual drives make fuller use of this command, copying programs from one diskette
to another in a single disk unit. To do that on the 1541, refer to Appendix E to find the
programs that you need.
COPYING PROGRAMS: BASIC 3.5
The Copy command allows you to make a spare copy of any program or file on a
diskette. However, on a single drive like the 1541, the copy must be on the same diskette,
which means it must be given a different name from the file copied. The source file and
other files on the diskette are not changed. Files niust be closed before they are copied.
Although the 1541 supports a Concatenate option, Basic 3.5 doesn't have a special
command for it. The Basic 2 syntax from the previous page may be used instead.
FORMAT FOR THE COPY COMMAND
COPY Ddrive #,"old file" to Ddrive #,"new file",Udevice #
where "D" is the drive number (always 0 on the 1541,) "new file" is the copy, "old
file" is the original, and "U" is the device number. If omitted, the drive number defaults
to 0 and the device number (unit) to 8.
EXAMPLES:
After renaming a file named "BOOT" to "TEMP" in the last section's example, we
can use the Copy command to make a spare copy of the program elsewhere on the
diskette, under the original name:
COPY "TEMP" TO "BOOT"
To copy a file on a second disk drive, we would use:
COPY "ORIGINAL" TO "BACKUP" ,U9
NOTE: Dual drives make fuller use of this command, copying programs from one diskette
to another in a single disk unit. To do that on the 1541, refer to Appendix E to find the
programs that you need.
VALIDATING THE DISKETTE: BASIC 2
The Validate command recalculates the Block Availability Map (BAM) of the
current diskette, allocating only those sectors still being used by valid, properly-closed
files and programs. All other sectors (blocks) are left unallocated and free for re-use, and
all improperly-closed files are automatically Scratched. However, this bare description of
its workings doesn't indicate either the power or the danger of the Validate command. Its
power is in restoring to good health many diskettes whose directories or block availability
maps have become muddled. Any time the blocks used by the files on a diskette plus the
blocks shown as free don't add up to the 664 available on a fresh diskette, Validate is
needed, with one exception below. Similarly, any time a diskette contains an improperly-
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