Return to BSD News archive
Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!msunews!agate!howland.reston.ans.net!news.sprintlink.net!helena.MT.net!nate
From: nate@trout.sri.MT.net (Nate Williams)
Newsgroups: comp.os.386bsd.questions
Subject: Re: Need HW/Drive purchase advice
Date: 2 Mar 1995 04:56:22 GMT
Organization: SRI Intl. - Montana
Lines: 45
Message-ID: <3j3j5m$n70@helena.MT.net>
References: <shamrock-1502952240270001@192.0.2.1> <3iv4ri$624@bonnie.tcd-dresden.de> <3j05a6$fhk@cynjut.infonet.net>
Reply-To: "Nate Williams" <nate@sneezy.sri.com>
NNTP-Posting-Host: trout.sri.mt.net
In article <3j05a6$fhk@cynjut.infonet.net>,
Dave Burgess <burgess@cynjut.infonet.net> wrote:
>In article <3iv4ri$624@bonnie.tcd-dresden.de>,
>J Wunsch <joerg_wunsch@uriah.heep.sax.de> wrote:
>}Lucky Green <shamrock@netcom.com> wrote:
>}
>}>I would like to run FreeBSD
^^^^^^^
....
>}>How much RAM should I add?
>}
>}Depends. If you're going to run X11, start with 16 MB total RAM.
>}
>}If you can effort it, $$ spent into RAM are never wrong (more RAM is
>}often the better choice as opposed to a faster CPU).
>
>One caveat on this. If you have a machine that is a straight ISA bus
>(not EISA, VLB, or PCI) and you try and use a bus-mastering SCSI
>controller, you can run into problems when using more than 16M of
>memory. It is a known, documented limitation of the ISA bus, and should
>not be ignored.
However, under FreeBSD this is not a problem. Even though there is a
penalty for using the upper memory (bounce buffers), that penalty is
trivial compared to the performance gain you are getting with a
bus-mastering SCSI controller.
At worst case, it is 15% slower to accesss memory w/bounce buffers.
But, memory is still a few orders of magnitude faster than disk, so this
is barely noticeable. It's a 'hack', but a very workable and usable
hack none-the-less.
Go for SCSI, as it'll never be a bad decision. You can always sell your
hard-drives to old workstation folks for swap disks, and your CD-ROMS
will always work on any machine. :-)
Nate
--
nate@FreeBSD.org | Do you think SRI cares what I say? They certainly
nate@sneezy.sri.com | don't accept responsibility for my actions, so I
work #: (406) 449-7662 | obviously don't represent them on Usenet.
home #: (406) 443-7063 | *FreeBSD core member and all around tech. weenie*