Path: utzoo!attcan!uunet!xstor!iverson
From: iverson@xstor.UUCP (Tim Iverson)
Newsgroups: comp.periphs.scsi
Subject: Re: Are "IBM" PCs Ready for SCSI?
Message-ID: <191@xstor.UUCP>
Date: 13 Jul 90 01:40:10 GMT
References: <23112@dartvax.Dartmouth.EDU>
Reply-To: iverson@xstor.UUCP (Tim Iverson)
Distribution: na
Organization: Storage Dimensions, Inc.
Lines: 53

In article <23112@dartvax.Dartmouth.EDU> stevel@eleazar.dartmouth.edu (Steve Ligett) writes:
>I read good things about the Adaptec AHA1542, but EDN didn't use it

Just out of curiosity, who (or what) is EDN?

>in their "All-Star PC" - because memory was remapped under the DOS
>extender they were using, and DOS was giving the card virtual addresses,
>not physical ones (*crash*).

QEMM386 (& DeskView) will allow you to not remap those areas that you do
not wish to remap.  I believe (but do not know for sure) that 386MAX does
also.  I suspect that other supported products do also - you'll have to
peruse the manual, though, in order to obtain the proper options.

>I just heard that the Future Domain controllers I'd been looking at
>don't work with Windows 3.0.

Usually this is more a function of the device driver rather than the
controller.  Are you sure that this was tested using the native DOS disk
device driver?

>It looks like the only controller that might not have compatibility
>problems is the Seagate (Future Domain) ST-02.  I'm told that it's a
>dog.

TMC830's (Future Domain's low end SCSI board) are one step up from ST-02's,
but that's not saying much - they still have a bug that will cause them to
poke a byte randomly into memory under the proper conditions.

Storage Dimensions makes a card that, in my opinion, is of higher
quality than the TMC830 and the ST-02.  It does out-perform the TMC830.
I don't know if it's been qualified for Windows 3.0 yet.

>Is this an accurate assessment of the state of SCSI in the PC world?
>The high-end cards are likely to be incompatible with the "high-end"
>software?  The low-end cards are just that?  Are there other choices?

Actually, if you're going to be running a single-tasking OS (i.e.
single-tasking from the point of view of the host adapter - only one command
to one drive at a time), the "high-end" controllers are actually slower
than the "low-end" due to the large amount of overhead on each command,
unless, of course, you are taking about the very highest end, a cacheing
host adapter, which will overcome it's command overhead by significantly
reducing latency and transfer time for a cache hit.

>Thank you for your advice.

Sure.

>steve.ligett@dartmouth.edu or ...!dartvax!steve.ligett

- Tim Iverson
  uunet!xstor!iverson