Using Macintosh external drives

[Mark R. Wallen]

Here is what I've uncovered empirically so far.  The Quantum ProDrive 80S
drives listed in the 4.0.X format.dat files (and thanks for the pointers)
seem to be different from the Quantum 280S drives in the Macintosh
external 80 meg drives that I have.  On my Sun 4/280 running 4.0.3 with a
'sc' (this is probably very important) SCSI controller, I could use format
to 'read' and 'write' (in analyze) using the ProDrive disk type.
Interestingly, (for me) was that there was a [defect table found] when I
selected the ProDrive type.  However, doing a format itself would always
fail on sector 3 (0/0/3), and "label" would fail writing the backup label
(near the end of the drive).

By chopping down the number of cylinders I was able to get a configuration
that would "label" happily.  (Note these disks were already formated
on/for a Macintosh so if the formats are the same I win/won big (and
did)).  Using the Quantum Prodrive format.dat entry and paring it down to
ncyl=764 and pcyl=766 got me something workable.  That means I could get a
working defect list written to the drive and mount and use it (I'm doing
so even as I type).  But I could never actually format the drives under
SunOS 4.0.3.  And I'm not real confident about doing a 'repair', should
that come up.

By going into 'analyze' before formatting and then doing 'setup", one can
select extended error messages.  The error message that you get when you
try to format seems to indicate that there are 823 cylinders and 31
sectors per track, not the 766 and 34 sectors per track that I was using.
Using a format.dat entry with those parameters did not work either (still
wouldn't format).  I also tried running a macintosh utility on the drive
to find out how many sectors it thought there were: 156272!  (Try running
that through /usr/games/factor!)

I have also discovered that I can only hang 2 drives off the sc controller
because the drives have external termination.  After adding drive 2, the
Exabyte, which is also on the sc controller, started failing with SCSI
parity errors.

I'm still tinkering away.  Thanks to all who responded.

Mark Wallen
Cognitive Science, UC San Diego
mwallen at ucsd.edu