about that hard disk vs. COM1 problem

Brian Smithson (brian@grot.ca41.csd.mot.com)
Sat, 11 Jan 92 8:55:02 PST

Well, I've been getting bounced around between NEC and the guy who wrote
the external hard disk driver. The driver guy claims that there was
some kind of firmware upgrade from NEC which fixed the problem. The
people I've talked to at NEC say that there has never been any kind of
firmware upgrade for the UltraLite. Grrr....

To restate the problem I'm having: I have a 21MB external hard disk connected
through the parallel port on the UltraLite floppy drive. Whenever data is
accessed on the external hard disk, I get some kind of corruption of data
on COM1. It shows up as erratic mouse behavior or as packet errors when
I'm downloading a file from a UNIX system over the COM1 serial line. It's
all recoverable stuff -- neither the mouse nor the downloads hang or anything
like that -- but it's really annoying. The problem seems to be exacerbated
by writes (as opposed to reads) of the external hard disk, and also by
COM2 activity. The mouse goes most crazy when I'm running GeoWorks Pro,
downloading a file over COM2 from America Online, and doing something using
the mouse in another GeoWorks window.

I did make substantial, albeit somewhat painful, progress. I had been using
the external hard disk as a Stacker drive. The 21MB physical disk was set
up as two Stacker volumes: 33MB and about 5MB. All that space was really
nice, but just for fun I backed up everything and undid the Stacker stuff
so that I would have a plain vanilla 21MB hard disk. The problem was
reduced, but not eliminated. I'm beginning to wonder if the UltraLite
interrupt handling just plain sucks. Has anyone else really exercised
LPT, COM1, and/or COM2 simultaneously and noticed any problems?

The next step I'm considering is getting a different external hard disk.
I noticed that D-C Drives in Texas (800-872-6007) offers a MicroSolutions
40MB parallel port hard disk for $429. Maybe the problem is that the
driver for my current hard disk sucks, and this one is better. I figure
that even if it is the same, at least the drive will be bigger!

In any case, I need to reach some kind of conclusion quickly. My 30 days
limit to return the current hard disk is nearing the end. Any suggestions
you might have would be greatly appreciated!

-- 
-Brian Smithson
 Motorola Inc., Computer Group, Commercial Systems Division
 10700 N. De Anza Boulevard, Cupertino, CA 95014 USA, (408)366-4104
 brian@csd.mot.com, {apple | pyramid}!motcsd!brian