jdr@cmu-cs-speech2.ARPA (Jeff Rosenfeld) (12/14/84)
[For what purpose is this `customary blank line'? ]
1. About 50 people have posted lists of C64 BASIC tokens.
2. When a disk is formatted (newed) an ID number is written someplace on the
directory. Whenever the Commodore makes a request for I/O, the disk drive
checks this ID number to make sure that it matches the one it has stored in
RAM. If it doesn't match, the controller re-reads the current BAM (that's
one of the blocks on track 18 that tells the drive controller which blocks
are used and which ones are free). If it does match, the controller assumes
that the same disk is still in the drive. If use use a unique ID number for
every disk you format, you won't have this problem. Nonetheless, it's good
programming practice to initialize the drive whenever your program calls for
disk swaps. That's what you get with a disk-drive that's more intelligent
than your computer.
3. Disk drive channels 0 and 1 are used by kernel when load or save
operations are called for. There is no real reason not to use them in your
programs unless your program calls for one of those operations (except
that it is usually advisable to respect your OS and not use something that
it reserves for itself - especially if you can just as easily avoid doing
so). This is mostly useful in machine language applications wher calls to
kernel's LOADRAM and SAVERAM might be common.
- Jeff Rosenfeld,
jdr@cmu-cs-speech2.ARPA.