SASI interface, SCSI devices...

From: Peter Sjoberg <peters04_at_techwiz.ca>
Date: Wed Feb 9 23:20:02 2005

On Wed, 2005-02-09 at 14:22 -0500, Steve Jones wrote:
> I'm looking around at a couple of situations where I may have
> a host with a SASI interface that needs mass storage. It would
> be preferable to just drop in a SCSI device and deal with
> whatever patching might be necessary, rather than using an
> ST-506 interface instead of SASI.
>
> Briefly Googling left me with the impression that hooking a
> SASI device to even an old SCSI contoller is pretty dicey, but
> no good feel for how well a random SCSI device might work with
> a SASI controller.
>
> Thanks,
> --Steve.

Some other people have answered to the sw part but I have some hw info.
A little while ago (early 80s) I was involved in converting our CP/M
system from SASI to SCSI (was doing CP/M BIOS programming) and the sw
part was not hard (who needs disconnect anyway?) but we had to put in
some extra loops on the connection (no controller here, just a PIO and
some TTL). IIRC the issue was around the bus phases and some extra line
(ATN?). Since all our configurations had only one disk we could cut lots
of corners in regards to selection etc but when taking two random
devices it may be more of a chance.
In our case we didn't need it but parity was another thing discussed
since some controllers required correct parity to accept any commands.


/ps
Received on Wed Feb 09 2005 - 23:20:02 GMT