From: rantapaa@s6.math.umn.edu (Erik E. Rantapaa)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: QUERY:is local bus/vesa killing EISA?
Summary: YES
Date: 7 Oct 92 06:02:08 GMT
Organization: University of Minnesota

fontenot@ravl.rice.edu (Dwayne Jacques Fontenot) writes:

>In article <1992Oct6.114126.1@sscvx1.ssc.gov> schludermann@sscvx1.ssc.gov writes:
>>
>>  Is Eisa dying? With many manufatures producing pseudo-eisa boards, eisa
>>boards using the eisa bus in isa mode by design, and the apparent scamble
>>of manufactures to produce local bus/vesa. Is this going to kill the advantages
>>of using a eisa machine?
>>                                 Kris

>I for one, would like to hear more about this. For example, I have heard that
>VLB does not have bus arbitration -- and that this is bad for multitasking OS
>use (like unix). Since I want a machine specifically to run unix and
>X-windows, I am thinking EISA is the way to go.

This is just my humble opinion, and is based entirely on what I have read
and heard in the last month, which is about when I started shopping for a
PC.  Like you I also want to run Unix and X, but would probably also
use Windows quite a bit and perhaps even OS/2.

For fast video you can't beat local bus.  Compaq makes a graphics
accelerator for EISA, and while it is fast, it doesn't measure up to
the latest ATI cards in either Windows or DOS video performance.
(See the October 27th, 1992 PC Mag for details.)  In addition, I'm not
sure how EISA performace scales with processor speed, but
theoretically you can double local bus throughput by going from a 33DX
to a 66DX2.  From what I know, I don't believe that a 66DX2 EISA would
give you that much more performace over a 33DX EISA, but I may be
wrong about this.

[BTW, your choice of video system may very well depend on which
version of Unix/X you decide to run.  The best supported chip set for
Xfree86 I think is the ET4000, whereas you can get real zippy
X-performance from Dell's Unix if you have an ATI card.  According to
the latest Xfree386 annoucement, you can get Xfree386 drivers for the
ATI and S3 cards from commercial sources.]

As for disks, I think someone mentioned that Ultra Stor makes a bus
mastering SCSI-2 controller for VESA local bus machines.  The bus
mastering feature may only work with certain motherboards (the guy
mentioned Micronics) if indeed local bus machines have trouble
implementing bus mastering.

My impression is that if you are going to hang a lot of peripherals off
your machine, (i.e. like a file server) go with EISA.  Otherwise, if
you just want your own personal Unix/X workstation, VLB is quite
adequete.  (It would be nice to get a VLB motherboard that had 3 local
bus slots so you could have one each for disk, video and ethernet.)

VLB is certainly here to stay.  It's simple design and cost
effectiveness give it price/performance ratio that's hard to beat.
You'll pay at least $300 more for a EISA motherboard.  EISA's major
advantage is expandability.  VLB has the advantage in performance and
cost.  In my opinion, EISA is becoming less relevent for the majority
of users, and its role is certain to diminish after the introduction
of PCI.

(If you want the best of both worlds, get a combination EISA/VLB
motherboard!)
--
"I think it's pretty sad that someone can take $300 million and try to
 buy the presidency of the United States.
                -- Marilyn Quayle, on Ross Perot, who, as of the time
                   she said this (May 29), had spent less than $2
                   million, versus Bush and Clinton's $15m+ apiece."

Erik Rantapaa    rantapaa@math.umn.edu