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From: j@narcisa.sax.de (J Wunsch)
Newsgroups: comp.os.386bsd.questions
Subject: Re: Need HW/Drive purchase advice
Date: 13 Mar 1995 11:19:32 +0100
Organization: Private U**x site, Dresden.
Lines: 22
Message-ID: <3k167k$eb7@bonnie.tcd-dresden.de>
References: <shamrock-1502952240270001@192.0.2.1> <3j05a6$fhk@cynjut.infonet.net> <3j3j5m$n70@helena.MT.net> <shamrock-0903951552350001@192.0.2.1>
Reply-To: joerg_wunsch@uriah.heep.sax.de
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Lucky Green <shamrock@netcom.com> wrote:
[ISA bus-mastering DMA devices need bounce buffers with RAM > 16 MB]
>I had just about decided on a Adapect 1542. But now I hear there might be
>problems using it on ISA with >16 MB. Do you think I'd better get a 1522?
No. They are PIO (programmed I/O), just like an IDE, and hence they
will also hog the CPU as IDE drives do. No good decision for a multi-
processing o/s. The penalty for the bounce buffers (if you happen to
have > 16 MB) is much less.
If you're buying a new machine and think about more than 16 MB RAM, do
also think about PCI and a PCI SCSI controller (e.g. NCR ...810), they
are rather cheap and do a good job -- and the bus doesn't suffer from
this ancient address space limit.
--
cheers, J"org private: joerg_wunsch@uriah.heep.sax.de
http://www.sax.de/~joerg/
Never trust an operating system you don't have sources for. ;-)