Subject: Re: AIC-78{6,5}00 support?
To: William O Ferry <WOFerry+@CMU.EDU>
From: Justin T. Gibbs <>
List: port-i386
Date: 08/11/1996 22:54:59
>The Pentium motherboards I'm interested in (I
>honestly wish I could remember the manufacturer, it looked like an ASUS
>clone) all have onboard Adaptec SCSI-II controllers.  One I believe was
>an AHA-2940AU, the controller chip was marked "AIC-78600".  Another was
>marked "AIC-78500", and a third (that I did not note the number on) was
>the same as the first, except it had both 50-pin and 68-pin (Wide SCSI)
>headers, so I'd imagine it's the wide equivalent to the 78500 chip.

The last motherboard *may* be a "2940 equivelent" meaning it uses either
a 7870 or 7880 chip.  A quick summary of the different chips:

SCB - SCSI Command Block (you need one of these for each active transaction
			  on the controller)
7850: 3 SCBs, 8-bit SCSI
7860: 3 SCBs, 8-bit Ultra SCSI
7870: 16 SCBs, 8 or 16-bit SCSI
7880: 16 SCBs, 8 or 16-bit Ultra SCSI

So, the last board you mention *could* be a "2940 equivelent".

>anybody tell me how well these chips are supported under NetBSD?  Will I
>regret upgrading (due to loss of support, stability, etc)??  Will the
>Adaptec be faster than the NCR?  Anybody know the difference between the
>78600 and 78500?

All of these chips are supported fine from 1.2beta on.  Of course, more
SCBs are better then less, so you should go with either the 7870 or 7880.

>                                                          Will Ferry
>William O Ferry <woferry@WarpDrive.COM> | finger:  woferry@WarpDrive.COM
>      | talk:  finger for online status

Justin T. Gibbs
  FreeBSD: Turning PCs into workstations