FORMAT PROGRAMS FROM MICROCORNUCOPIA AND SIG/M USER DISCS, AMENDED FOR
XEROX 820/1 WITH 8" SSSD DRIVES

FORMAT6.ASM
FORMAT6.COM
FORMAT4A.ASM
FORMAT4A.COM

I found that the formatting programs on MCC disc #1 did not work with my
Xerox 820/1 board, whilst the Format5 program worked some of the time with
some drives.  The problem with Format5 turned out to be quite simple:
it uses the highest speed version of the Seek command and my drives could
not keep up. Having fixed that, I could not leave well alone. I had
noticed whilst investigating that when the verify option is turned off,
the drive motor timed out part way through the format, so I added a SELECT
call to the monitor before each seek in case anyone wants to format without
verification. I also wanted the capability of formatting more than 77
tracks on certain of my oddball drives, and of formatting individual
tracks when trying to salvage disks which had fallen victim to hardware
misconduct.  So one can now specify (in hex) the first and last tracks to
be formatted.  This meant that I had to reformat the track display, and
there are some changes to the code setting up the track display since my
assembler cannot set memory bytes in the manner required by the original
code. The program will now accept lower case input (except that only Y
will confirm a track number above #76).

WARNING!  The program will warn you if you specify a last track greater
than #76, and ask you to confirm.  With a standard 77 track 8" drive, you
may risk damage to the drive if you attempt to format beyond track #76,
and CP/M will merely ignore the extra tracks unless the BIOS has been
altered appropriately.

After this, I wanted to find the problem with the earlier programs.
I use a 1791 rather than a 1771, and it appears that the 1791 at least
will not accept the input of a track number to its data register
preparatory to a seek command unless the interrupt generated at the
conclusion of a previous command has been reset. If the drive checks
out ready in the monitor SEEK routine, no such reset occurs. In order
to overcome this problem, and reduce the amount of drive activity, I have
replaced the SEEK routine in the formatting loop by the SELECT routine
followed by a direct seek command to the controller. An additional force
interrupt command also corrected a small bug in the verify routine, which
was failing to seek track 0 and verifying track 76 instead.

These programs worked well for me; I hope they may help others with    
formatting problems.

FFC.ASM
FFC.COM

This program comes from SIG/M disk 136.  It combines a disk formatter with a
very fast disk copy routine.  This version has been translated into Zilog
mnemonics, and tinkered with to get it to run with a Xerox 820/1 board at
4MHz. The program requires to know the starting address of your BIOS and the
drive motor turn-off timer location. These are set to 0EA00H and 0FF69 in
this version but can readily be altered: typical values for the BB1 are
0E800H and 0FF6CH.  To avoid reassembly, locations 036DH and 031AH in the
COM file can be altered.

Richard Parsons
RR#1 Mount Albert
Ontario L0G 1M0
(416)473-2488