🚀 go-pugleaf

In article <DCJun2.7ns@wombat.hanse.de>, root@wombat.hanse.de (Bernd "Bernie" Meyer) writes:
> medcalf@ppc5.svo.dfw.ibm.com (Jeff Medcalf (214) 280-5970 IBM SDO) writes:
> 
> >In article <DC566J.AC3@wombat.hanse.de>, root@wombat.hanse.de (Bernd "Bernie" Meyer) writes:
> >> philip@griffith.dwr.csiro.au (Frere) writes:
> >> 
> >> >AND your SCSI card is compatible with your SCSI device!  To cut costs in a 
> >> >cutthroat PC market, some SCSI functions are often left out making the card 
> >> >suitable for some but not all SCSI devices.  You then gotta make sure your 
> >> >device matches the card.  AMIGA and MAC don't have such pathetic limitations 
> >> >in the name of saving a couple of bucks!
> >> 
> >> Could you kindly elaborate on this one? I can't think of a single function
> >> you could leave out of a host controller that doesn't make the whole thing
> >> completely unusable. 
> 
> >I have seen PC SCSI cards that cannot:
> 
> >Boot from a device connected to that card
> 
> Only a BIOS limitation, and nothing to do with SCSI compatibility.

True, but irrelevant.  The measure of the usefulness of a SCSI card is
whether or not it can do what you want.  If it has a bad BIOS, then it
is not useful in some (many) cases.  The point of the post by Frere was
that SCSI on the PC is not the given that it is on the Mac (and, I presume
from my brother's experience the Amiga as well).

> >Co-exist with other boot devices (such as an IDE controller or another
> >  SCSI card)
> 
> The same.

See above.

> >Handle anything *except* a scanner of a particular brand
> 
> This, however, is most likely a problem of the scanner.

The scanner and card were tuned for each other, and neither would support
anything else.  Also see above.

> >Handle anything *except* a cd of a particular brand
> 
> This too.

See above.

> >Be unterminated (thus causing problems with adding both internal and
> >  external devices at the same time)
> 
> Yep, this is a real one. However, can Macs and Amigas switch from termintaed
> to unterminated without opening the case?

Macs do automatically.  Don't know about Amigas.

> >Support more than two devices
> 
> Nonsense. That's a BIOS problem. 

And drivers and DOS and a few other things.  But yet again, see above.

> >Support more than one IRQ setting on the card
> 
> Which doesn't really pose any SCSI compatibility problems, right? "Leaving
> out SCSI functions" is what we were talking about.

It's a semantic arguement.  I'm not talking about the signals used on the
cabling of the SCSI chain, sent between devices.  I am talking about what
the cards can or cannot do.  If a card cannot support more than one IRQ,
that is a problem.  The whole point is that PC SCSI cards are quite
often dismal, even when coming from well-known and generally good SCSI
card vendors.

> >Support more than three memory settings on the card
> 
> dito.

See above.

> >Some of these were "name brand," and some were not.  Most had to have
> >a real-mode driver loaded in order to handle drives larger than 1024
> >sectors (and some couldn't handle such drives at all) or to use drives
> >with IDs other than 0 or 1.
> 
> I think you are speaking about stupid BIOS and DOS extensions. And what the
> ^%^*^^&* is an SCSI drive "larger than 1024 sectors"?  Even under DOS, such
> a thing does not exist.

Pardon?  I am very confused by your statement that drives with more than
1024 sectors do not exist, since I have used quite a few of them.

> >Further, I've never seen a PC SCSI card/
> >driver combination that allows one to boot from a device with a non-0
> >SCSI ID.  This prevents, for example, hooking a known good hard drive
> >to the machine externally in order to diagnose problems with the machine.
> 
> I have seen many that simply boot from the _first_ found device. If you put
> your internal harddisk on ID 4, what you want to do is easy.

I left out the words "on DOS/Windows."  With OS/2 or Linux, I don't think
that the ID is significant.  It is when working under DOS.

> You haven't mentioned a single SCSI function that might be missing from
> PC-SCSI host adaptors that makes connecting your devices to it difficult. Of
> course, some SCSI adaptors don't implement synchronous operation, some don't
> provide disconnect/reconnect, most can't act as a target. But
> 
> a) None of this is needed to connect an SCSI device, and
> b) None of this is guaranteed to be available on either Mac or Amiga.

Again, that is not what I was talking about.  I was talking about how
in general the "cut any corner" mentality in the PC market has resulted
in a large number of SCSI cards (and others, really) which are absolute
crap.  And in fact, because of the way that Macs are designed and built,
and because of the quality standards in the Mac market, I have never seen
a single Mac or add-on Mac SCSI card which had any of the problems that
I mentioned in regards to PC SCSI cards that I have seen.

-- 
+-------------+-------------------------------+--------------------------+
|Jeff Medcalf | medcalf@interlock.dfw.ibm.com |                          |
|CTG-Dallas   | JKMedcalf@aol.com             | Power Series support     |
+-------------+-------------------------------+ SVMP/Tech Eval           |
|I not only don't speak for IBM,              | Comm Mgr/2               |
|I don't even *know* who speaks for IBM!      |                          |
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