Path: utzoo!mnetor!tmsoft!torsqnt!hybrid!scifi!bywater!uunet!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: A2091 PROBLEMS MUST BE RECOGNIZED! (Open letter to CBM)
Keywords: Anyone want to buy a A2500/30?
Message-ID: <18141@cbmvax.commodore.com>
Date: 27 Jan 91 02:42:35 GMT
References: <87541@tut.cis.ohio-state.edu> <51333@sequent.UUCP>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 57

In article <51333@sequent.UUCP> cseaman@sequent.UUCP (Chris "The Bartman" Seaman) writes:
>I've heard sufficient reports from people at Commodore, as well as users,
>to believe that, when done properly, disabling reselect for ALL drives
>connected to the 2091 will correct the lock-up problem.

	In doing further investigation I found that there is/was another
problem involving certain WD/rom revs, having to do with interrupt latency.
Some people may not have all their problems worked around by turning off
reselection.  This is dependant on machine type/configuration/drive type/
number of drives/rom rev/WD chip rev. (ugh)  I'm told the not-yet-released
roms will solve that problem also.  No, I can't say when they will be
released, sorry (even if I knew), or what the details will be.  (The
interrupt problem may also be fixed in one of the earlier 6.x rom releases,
I don't know for certain - I'm not the one who does the scsi device driver.)

>Although I don't (yet) have a second drive connected to my 2091, I went
>through the paces of disabling reselect, and found that it is very easy to
>THINK you completed the process, when in fact you have not.

	True.  Here's a step-by-step guide to disabling reselection:

Warning: it is possible to lose data in this procedure if a mistake is made.
Backing up the drive immediately prior to this is recommended for safety.
No warantee is stated or implied for these directions, they are written by
myself and are not an official statement of Commodore-Amiga.  You have been
warned.

First, go to the partitioning screen, turn on advanced options, and write down
all the info on all the partitions.  Particularily important are the cylinder
numbers, partition names, and bootable/bootpri.  Also write down anything
else you modified (bad block lists, masks, etc).

Go to the drive definition screen.  Read configuration from drive (which does
NOT read the RigidDiskBlock, it uses SCSI commands to ask the drive what
it's layout is).  Turn off reselection.  Change the name of the drive so you
can tell which one it is that you modified.  Select OK to save it in the drive
definitions file.  Select the drive definition you just created, and select OK.
It will tell you that all partitions will be lost if you save these changes.
(This was why you wrote down the partitioning info earlier.)  Select continue.
The main screen should now show the partition as changed.  Now go to the
partitioning screen, and restore all the information you wrote down earlier
(including any bad blocks from the bad block screen).

When you're certain you have it all set up right, select OK to get back to the
main screen, and then save changes to drive.  If you did things right, it
will not tell you that any partitions will be lost.  If it does tell you
that one or more partitions will be lost, then you made a mistake on the 
partitioning screen.  Cancel, go back to partitioning, and try again.

I have done this procedure on my drives to verify I had all the steps right.

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com  BIX: rjesup  
The compiler runs
Like a swift-flowing river
I wait in silence.  (From "The Zen of Programming")  ;-)