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From: markb@unix386.Convergent.COM (Mark Beyer)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Unix on 486 Machines
Message-ID: <7820@unix386.Convergent.COM>
Date: 18 Jun 91 21:25:26 GMT
References: <6408@w20-575-117.MIT.EDU> <284500026@adaptx1>
Organization: Unisys
Lines: 34

Me:
>>If your TCP stack just can't pump data down to the bus adapter
>>fast enough or, more likely, it can't receive it fast enough, maybe you're
>>OK with the (cheaper ?) ISA interface.

neese@adaptx1.UUCP writes:

>Using the 32 bit EISA bus and bus mastering, the
>ethernet card would utilize less of the bus I/O time, therefore allowing
>more time for other I/O (such as disk) to occur.  

But the ISA can do bus mastering already.  It's not the best implementation,
but it works in at least some environments.

>So many have looked at the EISA implementation from the perspective of, "WOW,
>now I can move data at 33MBytes/sec!"  Well, this isn't very pratical given
>the current state of I/O adapters/controllers and the peripherals that exist
>today (and for some time on the future).  

WRT hardware, I agree that you shouldn't consider just the EISA burst rate, and
there's certainly a lot of work to do with ethernet adapters, too.  But I 
still think the major bottleneck is performance in the implementation of the 
protocol stacks.  People have made progress, but there's a ways to go yet.

> But with that speed and a proper
>buffering implementation on the adapter/controller, more I/O's can be
>generated per slot than could ever be done on the ISA architecture.

Maybe true of disk I/O.  I was just speculating about network protocol
stacks.
-- 
Mark Beyer
markb@convergent.com
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