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From: minow@mountn.dec.com (Martin Minow)
Newsgroups: comp.sys.dec
Subject: Re: Sony Optical on DS3100
Keywords: Sony Optical Read/Write on DS3100 Ultrix 4.0
Message-ID: <1943@mountn.dec.com>
Date: 24 Sep 90 17:48:33 GMT
References: <9755@bunny.GTE.COM> <26615@boulder.Colorado.EDU> <2892@canisius.UUCP>
Reply-To: minow@bolt.enet.dec.com (Martin Minow)
Organization: Digital Equipment Corporation
Lines: 27

In article <2892@canisius.UUCP> pavlov@canisius.UUCP (Greg Pavlov) writes:
>
>  Disk performance on our DECstation 3100's don't seem to point to the presence
>  of a SCSI II capability...
>

The Ansi SCSI-II spec has several independent parts:

-- "hardware" such as the wide scsi bus enhancement.
-- "software" such as the extended command set and sense codes.

These are -- somewhat -- independent: a device can implement the SCSI-II
command set without the hardware bus enhancements.   However, the converse
is not true: the hardware enhancements, such as wide data transfer and
synchronous data transfer require negotiation as described in the
SCSI-II spec.

I suspect that the original poster was referring to the command set
capabilities.  These are, as far as I can tell, a superset of the
SCSI-I with "common command set."

I don't think any DECstations implement the wide or fast scsi bus
hardware enhancements.

Martin Minow
minow@bolt.enet.dec.com
The above does not represent the position of Digital Equipment Corporation.