Your message dated: Sun, 14 Jun 1998 21:53:10 -0400

Hi,

I haven't closely followed this thread, but thought I might have a few
comments based on my experience with similar problems:


>   2. In STANDARD MODE (AHA154x):
>
>           a)  Enable Parity Checking    [Y/N]
>           b)  Initial Synch Negotiation  [Y/N]
>           c)  Enable Disconnection      [Y/N]    ( asynchronous mode )
Start with: Y, N, N
Most HD's should work with: Y, Y, Y
I think quite some scanners won't do Sync and Disconnect (so, Y, N,N)
(at least mine doesn't). 

>           b)  Base Memory Cacheable         [Y/N]
>           c)  Extended Memory Cacheable  [Y/N]
No idea, really. But I always stay on the save side and ste them to NO.
I anybody could give me reason to lighten up this policy I'd be happy
to hear.

>           b)  BIOS support option      [HD/FR/NO] .... ( I always keep
>this in HD // fixed disk )
>           c)  Send Start Command      [Y/N]    ............ ( I think
>this is a constant NO )
I think, older disks don't need this (e.g. my Quantum TB) but some newer
do sometimes. Set it to Yes if your HD does not start spinning up at 
boottime and you want to boot from it (otherwise NetBSD will send the
start command later anyway  I think). 

>           g)  Max Synch Xfer rate       [10MB/s ...]  .... ( I hope
>someone will not ask me to try these out )
If your adaptec is an ISA card as is mine, do not set it higher than 5MB.
I don't know about EISA, but with ISA higher settings will produce errors
during heavy disk usage or not work at all...  You may want to start
with 5MB anyway, to be at the save side.

>  7.  The common sense tells me I should have disconnected my TAPE and
>CD-ROM
>       from the SCSI bus, and if I get a reasonable guidelines from the
>net I will do that.
I've had severe problems with a CD-ROM and Scanner attached to the bus.
Basically (I think) a lot of these devices do not stick to the SCSI standard 
very well or don't implement some optional features. Best to start
with such devices removed to see whether that helps. If you attach them,
start with Sync Neg and Disconnect set to NO in the Adaptec BIOS, as my 
experience is that these options are often not implemented by non-HD
SCSI devices and (worse) don't give a valid response when asked whether
they support the option.

>I think the relationships between the options 1, 2 and 4 above, or 1, 4
>and 5 are the key to the problem. Perhaps somebody out there knows what
>these are.

I hope the above helps you a bit. It's not info from an expert on the 
`underlying' issues, but is mainly based on experience I've had with an
ISA Adaptec 1542CF card with various, often rather old, SCSI devices.
Most of the tim, I ended up putting the blame on one of the SCSI devices
not on th Adaptec card. The extensive BIOS of the adaptec saved me
several times, due to its ability to switch of certain SCSI-options.
In a better world, such a thing should never be needed though.....

Good luck...

Feico Dillema.