Date: Wed, 6 Sep 1995 16:01:51 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: john@zyqad.co.uk (John Richards) Cc: freebsd-hardware@freebsd.org Subject: Re: SCSI - 1/2/3 fast wide Message-ID: <199509060631.QAA26051@genesis.atrad.adelaide.edu.au> In-Reply-To: <9509051511.AA07762@zyqad.co.uk> from "John Richards" at Sep 5, 95 04:11:09 pm
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John Richards stands accused of saying:
> The equipment in question is
>
> Toshiba XM5301B quad speed CDROM - SCSI-2
> Adaptec 2842 VL kit 32 bit to Fast SCSI adapter
> 540 MB Quantum Maverick Fast SCSI-3 512K cache 9.5ms disk
>
> I've been trying to find out:
>
> 1. Will these three actually work together
Should do just fine.
> 2. What is SCSI 1/2/3 fast wide etc - to try to solve 1
SCSI 1 : "old" SCSI spec, details disks & tapes.
SCSI 2 : "current" spec, adds CDroms & lots of other devices, adds
extensions for "fast" and "wide" operation, etc.
SCSI 3 : "evolving" spec, not formalised yet.
"fast" refers to an alternative way of handshaking data across the SCSI
bus. Most decent SCSI-2 disks do it. CDroms don't usually (not worthwhile).
"wide" refers to a 16-bit wide version of the SCSI bus. You need special
cables for this, and a "wide" controller. It is possible to put "narrow"
devices on a "wide" bus, but cabling can become a nightmare.
> 3. Is the quote really telling the truth about the disk. The SCSI-3 and 9.5ms
> access times don't tally with other adverts [Quoted access of 14ms]. Also I've
> got Rods post about the quantum range of drives.
Check www.quantum.com when your link improves; I'd trust Rod rather
than the quote. (There are other Quantum drives that fit the -3 and 9.5
spec, but I don't believe that the Maverick does.)
> John Richards * email : john@zyqad.co.uk
Hope that's some help.
--
]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[
]] Genesis Software genesis@atrad.adelaide.edu.au [[
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