Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uunet!comp.vuw.ac.nz!canterbury!cctr132
From: cctr132@csc.canterbury.ac.nz (Nick FitzGerald, CSC, Uni. of Canterbury, NZ)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: ISA/EISA
Message-ID: <1991Mar31.182147.361@csc.canterbury.ac.nz>
Date: 31 Mar 91 06:21:47 GMT
References: <1991Feb25.174455.1109@bronze.ucs.indiana.edu> <14111@hacgate.UUCP> <1991Mar28.114156.104@gnv.ifas.ufl.edu> <1991Mar30.222106.28919@bronze.ucs.indiana.edu>
Organization: University of Canterbury, Christchurch, New Zealand
Lines: 53

In article <1991Mar30.222106.28919@bronze.ucs.indiana.edu>,
ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib) writes:

[somebody else wrote the first bit, but Iskander hasn't attributed it]
>>ISA is Industry Standard Architecture, which is like what the IBM AT
>>had, a bus that could handle 8- and 16-bit cards.  EISA is Extended
>>ISA and is downward compatible with ISA cards.  An EISA slot can take
>>a 16-bit ISA, or an EISA-specific 32-bit card (the EISA card has a
>>special edge). So, the difference between ISA and EISA is the ability
>>to use 32-bit EISA cards. (An EISA PC may also have slot(s) for 8-bit
>>cards, I forget; but ask the dealer). 

An EISA PC _can_ have 8-bit only and 16-bit only slots, or all EISA.
 
> I suppose it would be useful to mention that most 386DX and 
> 486 computers with ISA buses also have 32 bit slots. These 
> slots are usually used for memory expansion, and are pro-
> prietary. 
> 
> Come to think of it, is there a "standard" 32-bit memory 
> expansion card that fits in the slots of large numbers of
> clone motherboards, or does EVERY motherboard have its own
> proprietary 32-bit card? I suspect there are 3 or 4 widely 
> used cards and slots that are shared by several manufactur-
> ers. 

I don't know if there is some sort of standard or not, but I recommend
anyone who buys a 386 that if they have the slightest inkling that they
may _someday_ want more RAM than fits on the motherboard, they should
obtain a 32-bit memory expansion board with their PC.  These usually
take SIMM's (sometimes SIPP's or just chips) which can be easily
purchased later (they are much more likely to be available in 3-5 years
than the correct expansion boards).  Generally you are looking at an
extra NZ$120-150 (US$65-80 ?) which is money well spent in my books.

I know two people who bought cheap-ish 386 clones a couple of years ago,
and whilst the outfit that sold them is still in business, still selling
what look like the same machines, they have different m/b's and the RAM
expansion cards for these are incompatible with their m/b's.  The
suppliers claim that the cards for the old boards are no longer available
as the manufacturers no longer make the m/b's so also stopped making the
expansion cards.
 
> (I remember giving a Zenith sales rep a really hard time 
> because she insisted the 32-bit slots in their machines 
> was ISA).

That's mean, cruel and nasty!   8-)
She was only doing her job!!    8-), 8-)

---------------------------------------------------------------------------
 Nick FitzGerald, PC Applications Consultant, CSC, Uni of Canterbury, N.Z. 
 Internet: n.fitzgerald@csc.canterbury.ac.nz        Phone: (64)(3) 642-337