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From: stripes@pix.com (Josh Osborne)
Subject: Re: The ultimate 386BSD machine? (FAQ fodder)
Message-ID: <Bvv82K.CA@pix.com>
Keywords: 386BSD
Sender: news@pix.com (The News Subsystem)
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Organization: Pix Technologies -- The company with no adult supervision
References: <1992Oct8.072512.8700@elroy.jpl.nasa.gov>
Date: Fri, 9 Oct 1992 17:47:06 GMT
Lines: 135
In article <1992Oct8.072512.8700@elroy.jpl.nasa.gov> earle@elroy.jpl.nasa.gov (Greg Earle - Gainfully Unemployed) writes:
[...]
>- I have seen some benchmarks whereby a 486DX2/66 outperforms a 486DX/50. But
> I saw a posting by Barry Shein that indicated that due to the bus speed on
> the former being only 33 MHz, this would not be a good idea as doing things
> like bitblts in X would be faster on a "native" 50 MHz system. This seemed
> perfectly reasonable, so it seems that a 486DX/50 is the best idea. Right?
With an ISA video card you are limited by the 8Mhz ISA bus, so 33Mhz/50Mhz
external speed won't make any diffrence there. The 66DX2 will do all of X's
FP code faster then the 50Mhz system. :-)
It really depends on what you are doing.
>- I saw a posting from Lynne Jolitz that I believe mentioned that a 32-bit
> disk controller was the best idea. I have assumed from subsequent postings
> that the Adaptec 1542B is the "controller of choice", no? OK, but that's
> an EISA board, correct? But now I'm confused, I thought that 386BSD didn't
> support "EISA machines". What's the deal?
It doesn't support EISA cards (but as you note below you can write support for
'em, but it is going to be more work). Also the 1542B is an ISA card. The
1742 is an EISA card.
> As an adjunct to this, I expect Julian to jump in with "But an Adaptec 1742A
> is supported with my new SCSI subsystem ... ". Fine, but can one get the
> system up first (with it installed) to get to the point where one can
> recompile the kernel with the new SCSI subsystem?
I think the 1742 in 1542 compat mode will normally be accepted by 386BSD as
an acceptable SCSI driver.
>- Of course, all of this begs the more fundamental questions, like
> "SCSI or IDE?" (to which I assume "SCSI" is the more correct answer ... ) and
If you are straped for money, or know you never want more then 2 drives and
no tape (like if you do backups over a network) then IDE is fine. SCSI costs
more and can handle more drives, and tapes, and other random things. Some
people say SCSI is way faster, others say IDE is a tad bit faster. I think
a good SCSI controler with a good SCSI drive is faster then a fast IDE
controler and fast IDE drive. IDE is cheeper for small disks, but seems to
cost more for big disks (say 1.2G, in fact the break even may be around 500M).
> what about these new VESA VL-bus systems that I'm seeing described in the
> new Byte, and that I'm seeing advertised in the new Computer Shopper? Any
> support for these? (I assume not ... )
I think VESA Local Bus looks like ISA cards except 32bit transfers arn't
converted to 16 (or 8) bit transfers, and they go at the clock speed of your
CPU, not 8Mhz like ISA. However most places are holding off on announcing
their VESA Local Bus until after the next CES (mid november). They are
good for fast video, but not needed for anything else (ISA is fast enough for
most disks, and much faster then ethernet), of corse having your video on
a local bus frees up the ISA bus for disk and ethernet traffic....
>- Video card support. Is that fancy SVGA card with 1Mbyte of video RAM that
> dealer XYZ wants to package into my neophyte's system compatible with XFree86
> or not? For example, I'd heard the bottom line was "no Diamond Stealth
> support until marriage!" (-: but then it seems like someone posted a little
> program to do clock twiddling so it would work. What's the Real Scoop on the
> video cards to buy? Can I just download vanilla X11 R5, apply the MIT
> patches, and then grab some XFree86 related patches from agate and apply
> those and turn gcc 2.2.2 loose on it, and expect that things will work? etc.
Non programabale clock ET4000's will work fine, the WD90C1X's (I think) also
work, but are slower. People are working on LOTS of other drivers, including
S3 drivers.
>- External cache. I had assumed "the more the merrier", like 128K. But I've
> seen people posting problems with external caches; either 64K or 128K was
> causing problems. No problems if they turn the cache off, which I assume is
> Not A Good Thing. What's the scoop on this?
Never saw any problems, I have 256K cache and it works fine. I'm not sure how
much cache BSD will really find useful (context switches tend to invalidate
cache, if not the contents, at least the usefulness of the contents), so I
wouldn't go out of my way to find a 512K cache (they exist!). Also most
systems will let you disable the cache, and many will let you change the size.
Oh, with 0.0 there was a problem where a delay loop was compled out of the
code so systems that were "too fast" couldn't boot. You may have heard
about that....
>- Serial ports; more trivial, but can I assume nowadays that I don't have to
> ask for NS16550AFN chips, and will get them by default? (I will want to run
> PPP at 38400 baud over them ... )
You will need to ask. To get the lowest price you may even need to buy your
system from a bubble-head who doesn't know what they are, and get the serial
card elsewhere.
>Given appropriate answers to the above, does anyone have any particular
>recommendations on system packages? Can one get a system without having
>MS-DROSS 5.0 and Windoze 3.1 thrown in? Is it better - assuming that if one
Yes, you can even get a motherboard with no CPU :-) How much assembly do you
want to do yourself?
>only wants to run 386BSD and not DOS - to buy "pick-a-part" fashion so that
>one doesn't have to pay for DOS and Windows, or is it better to buy a complete
>system from one of these gazillion system houses, and consider DOS and Windows
>as (unwanted) freebies? If the latter, does anyone have any recommendations
>on particular system houses/systems based on price and/or performance?
>Etc., etc.
It is easyer (by far) to buy a complete system. It is cheeper (by far) to go
to a local computer show (or buy for computer shoper) and buy picemeal.
However buy a computer shopper beforehand and read through it to get use to the
prices...
Oh, one place you may want to avoid is Gateway. They just buy large lots of
motherboards and stuff from whoever is the cheapest when they run low, so
they can't really give you better support then buying from whoever is the
cheapest when _you_ want to buy.
Eric Raymend (snark@someplace.or.other) has a fairly good guide to PC hardware.
[...]
>Any answers to the above would be greatly appreciated. As someone whose
>background has basically been nearly 9 years of Sun experience for the past 10
>years, buying one's first Computer Shopper and buying other PC-oriented rags
>to get info on things like CPUs and busses and the like quickly proves rather
>daunting, and it's hard to separate the wheat from the chaff when you're
>trying to determine that ideal 386BSD configuration.
Computer Shopper does seem to be the best place to look for PC prices (unless
you get clari.streetprices.*).
[...]
--
stripes@pix.com "Security for Unix is like
Josh_Osborne@Real_World,The Multitasking for MS-DOS"
"The dyslexic porgramer" - Kevin Lockwood
We all agree on the necessity of compromise. We just can't agree on
when it's necessary to compromise. - Larry Wall