Whats the screwiest thing you collect? - test-drb@ccmp.vtda.org

26 Nov 1999

As I have experienced them, bridge controllers have two types of interfaces.
One class is the HOST interface, often SCSI or SASI, and the other is the
target interface, e.g. ST506 or SMD, etc.  Though it's an easy mistake, it's
like asking whether a SCSI channel could drive the Q-bus via an Emulex SCSI
adapter.

While the data can flow both directions, the relationship is still one of
host and slave device.  In short, NO!  The SCSI <=> ESDI adapter won't let
you interface a SCSI drive via an ESDI host interface, unless, of course,
the ESDI is the host channel on the bridge adapter.

Dick

-----Original Message-----
From: Zane H. Healy &lt;healyzh(a)aracnet.com&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Friday, November 26, 1999 7:48 PM
Subject: Re: Whats the screwiest thing you collect?

...
  I collect
bridge boards.
I can't help it-- I have a fetish for bridge boards.  All makes:
Emulex, DTC, Xebec, WD, Adaptec, etc.  All kinds of configurations:
Cpu<->MFM (ala wd-1000), SASI<->MFM, SCSI<->ESDI, SASI<->QIC30,
all kinds.

The SCSI<->SMD configuration still eludes me, however.  I know
they exist (Adaptec ACB-55xx), though I've never seen one.  Docs
are *really* hard to get.  Still looking for the docs for the
Emulex MD-23, possibly the best darned SCSI<->ESDI bridge
ever made: Handles four drives at up to 24MHz data rate. Smokin'. 
Something I've been wondering about.  These boards look to have been used
to convert ESDI to SCSI for stuff like Apollo's and Sun's.  Could they be
used to convert a SCSI drive to work on an ESDI controller?

Feel free to ask if I'm out of my Freaking mind, I've never really taken
the time to look at them.  Actually not sure I want to know, I think I gave
the box of such things away.

 Zane
| Zane H. Healy                    | UNIX Systems Adminstrator  |
| healyzh(a)aracnet.com (primary)    | Linux Enthusiast           |
| healyzh(a)holonet.net (alternate)  | Classic Computer Collector |
+----------------------------------+----------------------------+
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