Date   : Sat, 23 Sep 1989 09:06:00 GMT
From   : jarvis.csri.toronto.edu!torsqnt!tmsoft!masnet!canremote!dan.copeland@rutgers.edu (DAN COPELAND)
Subject: 1581 Max-81 Format

There is a slight error in the 1581 MAX-81 format as published my Miklos
Gramskezky (in Transactor and in Twin Cities 128)

The error is in the DPH block (byte 20) of the drive table.  Basically 
what it involves is having the drive seeking track 80 in a (0-79 track 
system).  The fix is to change byte 20 from 90 to 8c this will restrict 
the drive to going from 0-79 and not access physical track 81 (which 
does not exist).

I found this and it was driving me nuts after I overfilled disks and had
to remove the disk from the drive or do a warmstart (^C) in order to 
read from that drive again.  You will loose 6K when you do a show 
command but that 6k wasn't really there anyways.
I sort of figured this when some disk utilities were showing 81 tracks @
1024 bytes per sector and I knew it should only read 80 tracks.. 
SHOW [DRIVE] didn't show this (and now reports 79 tracks) but 0-79 is 80
tracks in my thinking... Any further info needed
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