[net.micro.cbm] Answer: I/O to 1541 and BASIC tokens

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.