Path: utzoo!attcan!uunet!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.periphs.scsi
Subject: Re: Is DEC RZ23 real SCSI?
Keywords: Does DEC use some odd proprietary controller query scheme?
Message-ID: <12232@cbmvax.commodore.com>
Date: 4 Jun 90 05:24:40 GMT
References: <1990Jun2.213812.13909@spock.UUCP> <5454@crltrx.crl.dec.com> <1644@mountn.dec.com>
Reply-To: jesup@cbmvax (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 46

In article <1644@mountn.dec.com> minow@thundr.enet.dec.com (Martin Minow) writes:
>First, I would want to make it clear that I do not recommend that you
>connect a Dec RZ23 to a non-Dec computer.
>
>The RZ23 is a normal SCSI device. Drive formatters, however (I'm only
>familiar with the Macintosh) do a "device inquiry" to see what they're
>connected to.  The RZ23 responds with something like "DEC RZ23". If your
>drive formatter is looking for "QUANTUM P105S", it will fail with "don't
>understand this drive."

	Note that almost all Amiga HD controllers (including Commodore's
A590/A2091/A3000 controller and software) can deal with most any SCSI drive
that implements a reasonable portion of the CCS.  In particular, ReadCapacity,
Inquiry, and the standard R/W/request-sense/FormatUnit/etc commands.  In the
HDToolBox for the above-mentioned controllers, there's a "Read Configuration
from Drive" button that uses Inquiry, ReadCapacity, etc to attempt to figure
out a reasonable configuration for the drive.  This works pretty well, even
on zone-recorded things like quantums.  It may not be optimum, but it will
never waste much space on a disk.

	I think having to get custom formatting software for each drive is
a massive kludge/ripoff, IMHO.

>Also, vendors (not specifically Dec) often add proprietary microcode to
>the raw hardware.  For example, they may need to control certain kinds of
>error handling.  The Ansi standard reserves certain "mode select" and "mode
>sense" pages (records) to the manufacturer.  Some vendors (again, not
>specifically Dec) send a Mode Sense command and expect to see "Copyright 1990
>Mumble Corporation".
>
>In the PC market, when you buy a drive from an end-user vendor, it generally
>comes with a formatting package that understands its specific quirks.

	Not on the Amiga.  Just about any SCSI drive can be used, even stupid
drives that (for example) respond on all LUNs of their target address (we have
a dip-switch for that) or take 20 seconds to spin up (another dip-switch,
otherwise known as "seagate" mode).

	The symptoms imply either a) it's set up for address 7 (all amiga
scsi controllers I've seen default to 7), or b) it's totally stone dead, and
not even responding to SCSI messaging.

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.cbm.commodore.com  BIX: rjesup  
Common phrase heard at Amiga Devcon '89: "It's in there!"