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From: michaelv@iastate.edu (Michael L. VanLoon)
Newsgroups: comp.os.386bsd.questions
Subject: Re: PC Arch. > 16MB
Date: 12 Aug 94 07:45:52 GMT
Organization: Iowa State University, Ames, Iowa
Lines: 38
Message-ID: <michaelv.776677552@ponderous.cc.iastate.edu>
References: <32eve8$bg@bruce.uncg.edu>
NNTP-Posting-Host: ponderous.cc.iastate.edu
Keywords: memory, PC, EISA, VESA, PCI
cc: tuttlem@turing.uncg.edu
In <32eve8$bg@bruce.uncg.edu> tuttlem@bruce.uncg.edu (MattMan) writes:
>1. Do any of the IBM-PC architectures support the use of greater than 16
> megs of memory (ie: Do EISA,VESA, and PCI motherboards force the CPU to
> double buffer data to memory above 16 megs)? ~64 megs is my target
> memory configuration, but I don't want to tie up the CPU by forcing
> it to cart data.
The only bus limited to 16MB is ISA. Beware, though, some low-cost
cheapie VLB implementations are crippled, and can cause you problems;
likewise, there are some really scum-ball "EISA" boards on the market
that don't give you the full addressing either. But if your board has
true EISA, PCI, or VLB, you should have no problems with 64MB.
>2. Does *BSD take advantage of most features of VESA or PCI busses?
> Can I expect to get a significant portion of the thoroughput these
> busses "should" provide? I need at least sustained 1/4 meg output.
VLB is transparent, and I know of no VLB devices that don't work
(where the ISA counterpart does). NetBSD-1.0 has explicit PCI
autoconfiguration support. FreeBSD will support some PCI devices if
you do all the settings yourself. Both will support the entire line
of BusLogic SCSI controllers, including the PCI 946c. Plus there is a
beta driver for the NCR810 PCI SCSI chip that runs on both. EISA is
also well supported by both systems.
> One other question for the road. Is it better to purchase a Pentium
>or a 486? Why do you think so?
What do you mean "better"? I'm afraid you'll have to make that
determination yourself.
--
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Michael L. VanLoon Iowa State University Computation Center
michaelv@iastate.edu Project Vincent Systems Staff
Free your mind and your machine -- NetBSD free Un*x for PC/Mac/Amiga/etc.
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