Re: Adaptec AHA2940

Edward Welbon (
Fri, 3 Jan 1997 17:39:51 -0600 (CST)

On Fri, 3 Jan 1997, Bjarni R. Einarsson wrote:

> Researching mailing list archives gave me the following clues:
> 2. AHA-2940 wants to be in PCI slot #1.
> Basically the card seems pretty sensitive.. tip #2 solved my problem.
> Merely pulling the card out and moving it to another slot was what solved
> my problem. :-/

I have regrettably have many handfuls of various scsi controllers, of
these, the adaptecs are my favorites (I as yet have no buslogics). I think
that you might have some problem with the computer bios setup, the adapter
bios setup, perhaps a bad PCI connector, or just a instance of a flaky
card (It must happen, but it has never happened to me).

In my experience adaptec controllers are very good. One of my favorites
is the 1452, while not exceedingly fast, it seems to be able to talk to
any mixture of scsi devices (it is nice way to get the low bandwith
devices off of fast busses). I think that all of the major brands are all
pretty good.

You have to be careful that you don't have an infrequent device failure or
more likely, a bad cable. While the scsi specification prescribes a
number of constraints (e.g. the cable must not be flat against a chassis),
in reality, you can be pretty liberal with the routing, length and
positioning of connectors on scsi cables, but you can cause yourself

One culprit is the connection of the crimp-on connector "tangs" to the
individual ribbon cable conductors itself. It is easy for failures to
occur there, especially if the ribbons have mono-filament conductors. The
usual crimp-on connector will often not reliably contact the monofilament
conductors. The multi-stranded conducters having a larger diameter are
certain to make connection (this is unfortunate since electrically, the
monofilament cables are slightly better).

> I'm certainly not going to buy any more 2940's.

Neither am I, I have enough of them to last me a lifetime.

Ed Welbon;;

If you pick up a starving dog and make him prosperous, he will not bite
you. This is the principal difference between a dog and a man.
-- Mark Twain