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From: bill@bilver.uucp (Bill Vermillion)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: EISA vs. ISA
Message-ID: <1990Dec15.170839.5974@bilver.uucp>
Date: 15 Dec 90 17:08:39 GMT
References: <51097@eerie.acsu.Buffalo.EDU>
Distribution: usa
Organization: W. J. Vermillion - Winter Park, FL
Lines: 26

In article <51097@eerie.acsu.Buffalo.EDU> v127p9xg@ubvmsd.cc.buffalo.edu writes:
>
 
>If you purchase an MCA machine, all your conventional IBM-type cards are 
>useless. The question - why would anyone bother with MCA? because it comes with 
>the IBM name. I do not KNOW, but i have heard that MCA is inferior as far as
>potential for data throughput, but, since IBM invented & supports it, people
>(end users, 3rd party manufacturers of add-in cards, etc) have a tendency to 
>support it as well. 

MCA machines come with about a dozen different names on them as of this
moment, including Tandy, NCR, ALR and other.  As to inferior data
throughput, you are mistaken.   ALR is one of the few manufacturers that
uses both and EISA bus and an MCA bus.  Take a look at their specs for
their 25Mhz 486 machines.  THey are vitually identical except for the bus
structure.  The MCA machine has about two times the throughput of the EISA.
Why?  Take a look at the EISA which is limited to the 32 bits, and look at
ALR's implementation of MCA, 64 bit wide bus.   Not that this is pertinent
to the discussion but the MCA bus on IBMs RS/6000 series (in some models)
uses a buss that is 128 bits (16 bytes) wide.  THere are places where an
MCA bus has it's advantages.


-- 
Bill Vermillion - UUCP: uunet!tarpit!bilver!bill
                      : bill@bilver.UUCP