21,22



     See COMPUTE!, August 1982, for a useful program to create a
     small realtime clock that will continue to display during your
     BASIC programming. See also De Re Atari for another realtime
     clock application.

21,22          15,16          BUFADR
     Indirect buffer address register (page zero). Temporary pointer
     to the current disk buffer.

23             17             ICCOMT
     Command for CIO vector. Stores the CIO command; used to find
     the offset in the command table for the correct vector to the
     handler routine.

24,25          18,19          DSKFMS
     Disk file manager pointer. Called JMPTBL by DOS; used as
     vector to FMS.

26,27          1A,1B          DSKUTL
     The disk utilities pointer. Called BUFADR by DOS, it points to
     the area saved for a buffer for the utilities package (data buffer;
     DBUF) or for the program area (MEMLO; 743, 744; $2E7, $2E8).

28             1C             PTIMOT
     Printer timeout, called every printer status request. Initialized to
     30, which represents 32 seconds (the value is 64 seconds per 60
     increments in this register); typical timeout for the Atari 825
     printer is five seconds. The value is set by your printer handler
     software. It is updated after each printer status request operation.
     It gets the specific timeout status from location 748 ($2EC), which
     is loaded there by SIO.

     The new "B" type OS ROMs have apparently solved the problem
     of timeout that haunted the "A" ROMs; you saw it when the
     printer or the disk drive periodically went to sleep (timed out) for
     a few seconds, causing severe anxiety attacks in the owners who
     thought their Ataris had just mysteriously died. This is
     compounded when one removes a disk from the drive, believing
     the I/O process to be finished--only to have the drive start up
     again after the timeout and trying to write to or read from a
     nonexistent disk. Usually both the system and the user crash
     simultaneously at this point. See the appendix for more
     information on the new ROMs.

29             1D             PBPNT
     Print buffer pointer; points to the current position (byte) in the
     print buffer. Ranges from zero to the value in location 30.

30             1E             PBUFSZ
     Print buffer size of printer record for current mode. Normal