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From: michaelv@MindBender.HeadCandy.com (Michael L. VanLoon)
Newsgroups: comp.os.386bsd.questions
Subject: Re: SCSI controller recomendations requested
Date: 14 Sep 1994 18:42:12 GMT
Organization: HeadCandy Associates... Sweets for the lobes.
Lines: 50
Message-ID: <MICHAELV.94Sep14134212@MindBender.HeadCandy.com>
References: <Cw3nuw.E8@galaxia.network23.com>
NNTP-Posting-Host: stingray.cc.iastate.edu
In-reply-to: dave@galaxia.network23.com's message of Wed, 14 Sep 1994 03:18:32 GMT
In article <Cw3nuw.E8@galaxia.network23.com> dave@galaxia.network23.com (David H. Brierley) writes:
I am looking to put a new SCSI controller in my machine and I wanted
to get some opinions first. The machine is a 486DX/40, ISA/VLB
[...]
Adaptec 1542CF (ISA)
Slow. Buying it supports Adaptec's fascist support policies with your
own dollars. Limited to 16MB of memory on some systems, and even on
newer systems, will be slower above 16MB. The ISA bus is 16-bits wide
and runs at 8MHz.
Bus Logic BT545S (ISA)
Same limitations as the Adaptec 1542 (they're practically the same
card, feature-wise).
Bus Logic BT445S (VLB)
This is really the only choice that makes sense. It's twice as wide
and four to five times as fast as anything on your ISA bus. Plus, it
can access any RAM you put in your machine without resorting to
bounce-buffer slowness. The VLB bus is 32-bits wide and runs at (in
your machine) 40MHz.
One thing that I am really confused about is the issue of ISA vs
VLB for the SCSI controller. A friend (who has been using PCs for
a long time) told me to avoid VLB for the disk controller but
obviously some people are using VLB because otherwise why would
FreeBSD include support for it? Should I use the VLB version?
You should avoid using VLB for a disk controller *IF* you have a
better bus to use (i.e. EISA or PCI). Since your only alternative, is
ISA, which is much worse than VLB, then you should use VLB for your
SCSI. One thing to watch out for is that some motherboards have only
one master slot, and then some slave VLB slots -- you want to make
*sure* your VLB card gets into the master slot.
I.e. would it be faster? I have a VLB video card already installed.
ISA will never be faster than VLB.
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Michael L. VanLoon michaelv@HeadCandy.com michaelv@iastate.edu
Free your mind and your machine -- NetBSD free un*x for PC/Mac/Amiga/etc.
Working NetBSD ports: 386+PC, Mac, Amiga, HP300, Sun3, Sun4c, PC532
In progress: DEC pmax (MIPS R2k/3k), VAX, Sun4m
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