2nd hard disk controller

[Bill Blue]

In article <1116 at ispi.UUCP> jbayer at ispi.UUCP (Jonathan Bayer) writes:
>I am using a Western Digital WD1006V-MM1 controller.  The controller has
>been modified to make it use interrupt 15 instead of 14.  It has been
>strapped for the alternate address.

I take it then, that you have the app notes from SCO that talk about
all this, and you've got the kernel modified for the number of drives
etc., etc.

>I have attached a Seagate 4051 hard disk.  This is the third hard disk
>in the computer.
>
>The computer is an Everex Step/25 system.
>
>The problem:  every once in a while, the system will lock up while
>accessing the third hard disk.  I can duplicate the lock up by doing a
>bad track scan of the hard disk, specifying a thorough scan.  Within
>three or four cylinders the system will lock up.
>
>I have tried this with another hard disk, with the same results.

Define 'once in a while'.  Daily?  During heavy disk usage?  And is
this 2.3.1?

I have a Datel (Trans) 386-25 with three drives.  The primary
controller is a DTC 6280 ESDI controller with a CDC 182 as drive one
and a CDC 442 as drive two.  The second controller is a DTC 7187 RLL
with one Maxtor 120mb (RLL'd to just under 200) drive.  Other than the
Maxtor having a much slower seek rate (quite noticeable) things seem
to work fine.  Much of the time I don't have the third drive mounted,
but when I do it is there for most of the day.

Before I added the CDC 442 as drive 2, I was using the CDC 182 as
drive one on controller one, and the Maxtor as the second drive as
drive one on the second controller.  (Did you follow that??)  Anyway,
continued with that for a little over a week handling full news and
lots of other activities with no problems.  That's not quite the
same as three drives, but it is making use of the second controller
heavily.

This really won't provide any answers to your problem, but is fyi.  If
you need any of the SCO docs on any of this, I've got some faxed
copies I could send you.  It took me 2+ weeks to track all this down
and to finally get to SCO people that knew a) what I was trying to
accomplish and b) how to do it.  And this was going through dealer
channels.  Glad I wasn't in a hurry.

--Bill

(one other thing I noticed on these controllers was that there was a
signficant performance difference depending on how the select jumpers
were set -- I forget the jumper number, but it deals with whether the
drive should deselect or stay selected after each access.  Deselecting
caused noticeable delays in subsequent accesses, so leave jumpers set
to keep the drive selected until a different drive is requested.)