ESDI vs SCSI

[Phil Hughes]

In article <2422 at cps3xx.UUCP>, usenet at cps3xx.UUCP (Usenet file owner) writes:

> I can't comment on ESDI vs SCSI. However, at work I have on my desk a 
> 12.5 MHz 286 box using a 40MB Quantum SCSI drive with SCO XENIX 2.2.3.
> I am the only one hooked to the machine (w/ 4MB RAM). The through
> is just fine. One word of warning, since the kernel needs the SCSI
> driver installed, you have to gen a kernel on a machine with a normal AT
> drive and make a new N1 disk. I assume this is the same case for ESDI.

Most ESDI controllers are willing to look like a regular Western Digital
interface to the AT bus.  Therefore you can use the ST506 driver with an
ESDI controller.  SCSI, however, does require a different driver.  SCO
offers one - if you buy 386 XENIX you need 386-GT instead of 386-AT.
I just found this out today.  They seem a little confused internally about
it as well.

> I've always been under the impression that ESDI is faster than SCSI. Or
> is this a mistaken impression? I think I can safely say that SCSI is
> cheaper then ESDI.

I am running ESDI drives on a 386 system running ENIX.  It is fast.  On
the other hand I have a friend running SCSI drives on Rat Shit XENIX.  It
os probably faster.  The reason is that the SCSI driver is smarter as is
the SCSI controller.

As for price, I found 100MB ESDI drives for $525 each.  That is what I
call cheap but the deal is long gone.  The prices seem to be about
equivalent.
-- 
Phil Hughes, SSC, Inc. P.O. Box 55549, Seattle, WA 98155  (206)FOR-UNIX
    uw-beaver!tikal!ssc!fyl or uunet!pilchuck!ssc!fyl or attmail!ssc!fyl