Commodore 1581 - Renaming and Scratching Troublesome Files; Collect Command

This example deletes all files with one-character names.
Depending on the exact problem, you may have to be very
creative in choosing pattern-matching characters that will affect only
the desired file, and may have to rename other files first to keep them
from being scratched.
In some cases, it may be easier to copy desired files to a different
diskette and leave the troublesome files behind.
COLLECT
The COLLECT 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 reuse, and all improperly
closed files are automatically scratched. However, this brief descrip
tion of COLLECT doesn't indicate either the power or the danger of
the 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 3160 available on a fresh diskette,
COLLECT is needed (with one exception below). Similarly, any time a
diskette contains an improperly closed file (splat file), indicated by an
asterisk (*) next to its file type in the directory, that diskette needs to
be collected. In fact, but for the one exception below, it is a good idea
to COLLECT diskettes whenever you are concerned about their integ
rity. Just note the number of blocks free in the diskette's directory
before and after using COLLECT. If the totals differ, there was indeed a
problem, and the diskette should probably be copied onto a fresh
diskette file-by-file, using the COPY command described in the pre
vious section, rather than using a backup command or program.
The exception is diskettes containing direct access files, as de
scribed in Chapter 6. Most direct access (random) files do not allocate
their sectors in a way COLLECT can recognize. Thus, collecting such a
diskette may result in unallocating all direct access files, with loss of all
their contents when other files are added. Unless specifically instruct
ed otherwise, never collect a diskette containing direct access files.
(Note: these are not the same as the relative files described in Chapter
5. COLLECT may be used on relative files without difficulty.)
FORMAT FOR THE COLLECT COMMAND
COLLECT [Ddrive#] [,Udevice#]
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