THe trouble comes in trying to bind the requirements outlined in many disk
controller manuals with the jumpering schemes on one drive type, often not the
one you have, to the meaning of those jumpering option so you can translate
that into equivalent jumpering on another drive type not on the list of drives
for which there are jumperings specified by the controller manufacturer. The
defaults tend, generally, to be equivalent, but the various controller makers
tended to opt for configurations that made their particular controller work
better, or what they so deemed, than some other controllers. This can lead to
severe confusion if the "definitions" of those options are not characterized.
Once some drives started using microcontrollers or other LSI's for their
devices, things became murkier. Often it was possible to divine what a given
jumper was supposed to do by looking at the similarly named jumper on a
previous model of drive, but that didn't always work.
more below ...
Dick
----- Original Message -----
From: "Tony Duell" <ard_at_p850ug1.demon.co.uk>
To: <classiccmp_at_classiccmp.org>
Sent: Monday, January 14, 2002 12:34 PM
Subject: Re: 8" Disk drives
> >
> > Did the CDC/MPI Hardware Maintenance Manual include the jumper options and
> > setup details? I recall that the Mitsubishi, Shugart, and Qume
maintenance
>
> Sort-of. It tells you which of the factory-set jumpers are fitted for
> each version of the logic board. It also points you to the right page of
> the schmatics for setting things like the drive select jumpers.
>
>
> > manuals didn't, and the Siemens, though they showed the various circuits,
> > didn't explain what they did. The one most often needed is the OEM
manual.
> > That's the one with the installation and setup data, as well as the
spec's.
>
> On these drives, the logic is almost all simple TTL. It's easy to work
> out what most of the jumpers do from the schematics (which are in the
> maintenance manual). To be honest I'd rather have the schematics (from
> which I can work out the jumper settings) than a table of jumper settings
> (from which I can't work out the schematics).
>
> The really annoying ones at the modern-ish Teac manuals. On those drives
> there's one big ASIC for everything. Jumpers just connect pins of it
> together, or pins of it to external connector pins. So it's impossible to
> work out what they do, even with the schematics. And Teac don't include
> the jumper table in the manual.
>
Well, they do LIST the jumpers, but they don't tell you what they're intended
to do for you.
>
> >
> > Those are lots more common than the maintenance manuals as well.
>
> I've never seen the OEM manual for any of the drives I work with. I've
> seen references to it in the maintenance manaul, so it must have existed,
> but the maintenance manuals are a lot more common over here.
>
> >
> > If you need the maintenance manual, you're in BIG trouble, particularly if
you
> > haven't got it.
>
> Well, most electronic faults are not hard to put right on these drives
> given the schematics....
>
> -tony
>
>
Received on Mon Jan 14 2002 - 15:06:50 GMT