ssingh@watserv1.waterloo.edu ($anjay "lock-on" $ingh - Indy Studies) (02/17/90)
In article <2221@ultb.isc.rit.edu> cms2839%ritvax.bitnet@cunyvm.cuny.edu writes: > that's funny . i've got the issue right >here , and it says that the Editor's Choices were the AST , the _Austin_ >, and the Zeos ... > Sorry for the mistake. I must have confused all the good things that have been said about gateway's machines with the stuff in the magazine. I stand corrected. I was wondering about the competing bus standards, EISA and Micro Channel. Not being too familiar with PC architectures yet (my last machine was a 64) I was wondering if someone could explain what this means for PC board performance for peripherals and CPU throughput. In other words, how does it work? Or where can I go to find out? It doesn't appear to be as simple as the SX/DX confusion, where all we are talking about is memory bus bandwidth. If this question has been asked before, I'm sorry. Perhaps it could be taken care of in the frequently-asked-questions file that is currently being prepared. Thank you. -- "Nobody had the guts...until now..." |-$anjay "lock [+] on" $ingh ssingh@watserv1.waterloo.edu N.A.R.C. ]I[-| "A modern-day warrior, mean mean stride, today's Tom Sawyer, mean mean pride." !being!mind!self!cogsci!AI!think!nerve!parallel!cybernetix!chaos!fractal!info!
cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) (02/27/90)
In article <1132@watserv1.waterloo.edu> ssingh@watserv1.waterloo.edu ($anjay "lock-on" $ingh - Indy Studies) writes:
$I was wondering about the competing bus standards, EISA and Micro Channel.
$Not being too familiar with PC architectures yet (my last machine was a 64)
$I was wondering if someone could explain what this means for PC board
$performance for peripherals and CPU throughput.
Just to make sure we're straight here, EISA and MicroChannel are both
I/O bus designs, and have nothing to do with the main processor (unless
the board you're plugging in is an expansion memory board).
Now for some history. The original PC bus was 8 bits wide, since the
8088 appears to be an 8-bit processor to the outside world. When the
AT came along, using the 80286 with a 16-bit interface, the PC bus was
expanded to 16 bits. This is referred to as ISA, for Industry Standard
Architecture, and is what you'll find in most 386SX machines (and until
EISA came along, most 386DX machines use simple extensions to it).
When IBM designed the PS/2 family, they figured they'd had enough of
other companies building clones, so they designed a new bus. Well, that's
a bit jaded ... the MicroChannel supposedly is designed for multiple bus
masters and has some other nifty features to improve throughput, but IBM
also wanted to try to do away with a lot of the competition. MicroChannel
is not compatible with ISA ... it uses different sized cards, different
sized connectors, and has a whole pile of different signals.
Seeing what IBM was doing, a group of (nine, I think) companies got
together to propose an enhancement to ISA, called EISA, which would be
compatible with all the old ISA cards and also provide a high-speed
standard for 32-bit I/O boards as well.
Which is better? It depends on who you listen to. In any case,
the theoretical capabilities of each bus exceed the level of current
I/O cards (I think they both have burst transfer rates of around 40
MB/s, for example), so there isn't really a performance advantage to
one or to the other. Personally, I'd stick with EISA for a few reasons:
- for any function that exists on an expansion card, you'll find it on
an ISA card but not necessarily on a MC card
- ISA/EISA cards are cheaper to design and produce than MC cards, since
MC cards are a _lot_ smaller and virtually require surface-mount
technology and custom VLSI chips so that you can fit everything on
a board. This was a move on IBM's part to help ensure that they'd
have less competition.
- if you're upgrading an old PC, your old cards will still work in an
ISA/EISA machine, whereas to go MC you'll have to replace them _all_.
I guess I should state that all anti-IBM opinions here are strictly
my own, though a lot of people would agree with them :-)
--
Stephen M. Dunn cs4g6ag@maccs.dcss.mcmaster.ca
<std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
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I Think I'm Going Bald - Caress of Steel, Rushnghiem@ut-emx.UUCP (Alex Nghiem) (02/27/90)
In article <25E97CF2.6432@maccs.dcss.mcmaster.ca> cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) writes: >- if you're upgrading an old PC, your old cards will still work in an > ISA/EISA machine, whereas to go MC you'll have to replace them _all_. Gotcha! (:->) There are PC/XT boards that will not work in even an AT machine no matter how hard you try. I have an Everex Evercom 1200 that refuses to work in anything other that a PC/XT bus. It appears that bus speed/timing is the issue here. But, I do agree that ISA/EISA is designed to work with the older cards. __________________________________________________________________________ This article is posted for factual information only. Any misrepresentation, if any, is purely unintentional. Any opinion expressed or implicit in these remarks are solely my own. nghiem@emx.utexas.edu !cs.utexas.edu!ut-emx!nghiem nghiem@walt.cc.utexas.edu !cs.utexas.edu!ut-emx!walt!nghiem
kevinc@cs.AthabascaU.CA (Kevin Crocker) (03/02/90)
In article <25E97CF2.6432@maccs.dcss.mcmaster.ca> cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) writes: >expanded to 16 bits. This is referred to as ISA, for Industry Standard >Architecture, and is what you'll find in most 386SX machines (and until >EISA came along, most 386DX machines use simple extensions to it). > >together to propose an enhancement to ISA, called EISA, which would be >compatible with all the old ISA cards and also provide a high-speed >standard for 32-bit I/O boards as well. O.K. Now, which machines have this EISA thing. I am thinking of buying an AST Premium 386/33 (CUPID Technology) with 4Mb and a 387. Would this thing be EISA? What happens when I plug in a special video card and monitor e.g. Pixelworks UltraClipper 256 card and a Taxan UV1150 monitor? Kevin -- Kevin "auric" Crocker Athabasca University UUCP: ...!{alberta,ncc,attvcr}!atha!kevinc Inet: kevinc@cs.AthabascaU.CA
cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) (03/03/90)
In article <569@auvax.AthabascaU.CA> kevinc@cs.AthabascaU.CA (Kevin Crocker) writes:
$O.K. Now, which machines have this EISA thing.
Right now? Very, very few. HP has one, and so does Zenith, but they're
the only two I'm aware of (there are probably others I haven't heard of).
In any case, check with two or three dealers to see what they say (you
know dealers, most of them don't have a clue about the insides of the
machines they're selling).
--
Stephen M. Dunn cs4g6ag@maccs.dcss.mcmaster.ca
<std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
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I Think I'm Going Bald - Caress of Steel, Rushflint@gistdev.gist.com (Flint Pellett) (03/06/90)
cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) writes: >In article <569@auvax.AthabascaU.CA> kevinc@cs.AthabascaU.CA (Kevin Crocker) writes: >$O.K. Now, which machines have this EISA thing. Olivetti has a machine with EISA that was reviewed in MIPS (now Personal Workstation) magazine, but I don't know if they are actually shipping it. It was around a $20K machine I believe. (It is a dual-processor machine, with both a 486 and 860 in it- the reviewed machine didn't yet have the EISA VGA card, etc. though.) Compaq has a more normal workstation: a 486 machine with EISA available, (shipping next month, I was told) on which I got a quote for around $12K (that includes a 300MB disk but no monitor or graphics card.) ($17.5 list) I have not heard of any EISA machines cheaper than that: nor have I heard of any 386 machines that are EISA- nobody seems to be putting that bus into anything except high-end workstations or bigger. I don't think anyone is really taking advantage of the EISA much either- there aren't very many boards out for it yet. I concluded (somebody let me know if they think I'm wrong) that if you have to pay extra for EISA right now you're not buying much if any extra capability now, but you're buying potential extra capability in the future. -- Flint Pellett, Global Information Systems Technology, Inc. 1800 Woodfield Drive, Savoy, IL 61874 (217) 352-1165 INTERNET: flint%gistdev@uxc.cso.uiuc.edu UUCP: uunet!gistdev!flint
cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) (03/06/90)
In article <888@gistdev.gist.com> flint@gistdev.gist.com (Flint Pellett) writes:
$[...] I have not heard of any EISA machines cheaper
$than that: nor have I heard of any 386 machines that are EISA- nobody seems
$to be putting that bus into anything except high-end workstations or
$bigger. I don't think anyone is really taking advantage of the EISA much
$either- there aren't very many boards out for it yet. I concluded
$(somebody let me know if they think I'm wrong) that if you have to pay
$extra for EISA right now you're not buying much if any extra capability
$now, but you're buying potential extra capability in the future.
Well, Zenith has a 386/33 with an EISA bus, and an EISA disk
controller (see February 1990 BYTE). Expect to see more 386-based
EISA machines in the not-too-distant future.
--
Stephen M. Dunn cs4g6ag@maccs.dcss.mcmaster.ca
<std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
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I Think I'm Going Bald - Caress of Steel, Rush