Commodore 1541-II - Housekeeping Hints

HOUSEKEEPING HINTS
Hint #1: It is best to open file 15 once at the very start of a program, and only close it at
the end of the program, after all other files have already been closed. Do this because
closing the command channel automatically closes all other disk files. By opening once at
the start, the file is open whenever needed for disk commands elsewhere in the program.
Closing it at the end makes sure air disk files are properly closed without interrupting any
other file commands.
Hint #2: If Basic halts with an error when you have files open, Basic aborts them without
closing them properly on the disk. To close them properly on the disk, you must type:
OPEN 15,8,15:CLOSE15
This opens the command channel and immediately closes it, along with all other disk
files. Failure to close a disk file properly both in Basic and on the disk may result in losing
the entire file!
HINT #3: One disk error message is not always an error. Error 73, "CBM DOS 2.6
1541" will appear if you read the disk error channel before sending any disk commands
when
you turn on your computer. This is a handy way to check which version of DOS you
are using. However, if this message appears later, after other disk commands, it means
there is a mismatch between the DOS used to format your diskette and the DOS in your
drive.
HINT #4: To reset drive, type: OPEN 15,8,15,"UJ" Then wait until the drive activity
LED is off and motor goes off, then type: CLOSE 15. This also applies to sending a UI +
oraUI-
SAVING PROGRAMS: BASIC 2
Before you can save a program to diskette, the diskette must be formatted, as
described earlier. Saving to diskette is just like saving to cassette, except that the device
number of the disk drive is not optional.
FORMAT FOR THE SAVE COMMAND
SAVE * 'drive #:file name*' ,device #
where "file name" is any string expression of up to 16 characters, preceded by the drive
number (always 0 on the 1541) and a colon, and followed by the device number of the
disk, normally 8.
However, it will not work in copying programs that are not in the Basic text area,
such as "DOS 5.1" for the Commodore 64. To copy it and similar machine language
programs, you will need a machine language monitor program. Its use
for this purpose is identical to the monitor save described on the next page under
Basic 3.5.
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