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From: jrd@cc.usu.edu
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: SCSI confusions, help please!
Message-ID: <1991May22.150629.47872@cc.usu.edu>
Date: 22 May 91 21:06:28 GMT
References: <TIMS.91May16115641@infidel.infidel.lanl.gov>
Organization: Utah State University
Lines: 46

In article <TIMS.91May16115641@infidel.infidel.lanl.gov>, tims@infidel.lanl.gov (Tim Sullivan) writes:
> 
> I am confused about the SCSI interface. Let me describe the problem I
> was trying to solve and hope that someone can explain why I was wrong.
> 
> A Sun network here at the Lab needed more disk space and tape backup,
> so they went out and bought an external box from R-Squared that has a
> 1.2Gbyte hard drive and a 2.3 Gbyte Exabyte tape drive. It interfaces
> to a Sun throught the Sun SCSI port. No problem.
> 
> Now we have an AT and a frame grabber that takes data off of a video
> camera. For something that we want to do, we are limited by the size
> of our hard disk, which coincidentally died. So we said, why don't we
> replace the dead MFM hard disk with a small SCSI disk and when we need
> to we can bring the R-Squared system over and use with the AT? A 150Mb
> SCSI drive might cost us $750 or so, and a SCSI controller can be
> found for less than $100. So, for less than double the price of an MFM
> hard drive of comparable size, we can switch to SCSI and have the
> occasional use of the big disk and tape drive.
> 
> I've heard that you should buy the SCSI controller from the same
> people you buy the disk from, so I looked in the R-Squared catalog and
> sure enough, they sell a SCSI controller to attach their drive to an
> AT for $1600! And a 91 Mbyte, internal hard drive for $1725! 
> 
> So what is wrong here? What is it about SCSI controllers that can
> support price differences so large? What does a $1600 controller do
> that a $100 controller doesn't do? There must be something I don't
> understand. 
> 
> Thanks for any help you can offer.
> 
> Tim Sullivan (tims@goshawk.lanl.gov)
---------------------
Tim,
	Yup, a misunderstanding. It is possible to spend $1600 on a SCSI
controller for an AT, but you have to work hard on it. That's the price
for a VAX SCSI controller.
	Ask R Squared for an Adaptec 1542B controller (under $300) and
a good drive (680MB units go for $1500-1700 these days as a benchmark figure).
Adaptec supplies drivers with their "kit" package at that price. If they
can't provide then feel safe in purchasing the controller from an official
Adaptec distributor and use it with almost any SCSI drive around. The under
$100 controllers are too simple minded for a high performance drive (recall,
these things escalate into more and bigger drives).
	Joe D.