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From: dr@ski.UUCP (David Robins)
Newsgroups: net.micro,net.arch
Subject: Re: Apple's IWM; Floppy Disk Controllers
Message-ID: <224@ski.UUCP>
Date: Tue, 21-Jan-86 20:04:58 EST
Article-I.D.: ski.224
Posted: Tue Jan 21 20:04:58 1986
Date-Received: Thu, 23-Jan-86 21:24:36 EST
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Organization: Smith-Kettlewell Institute, S.F., CA.
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Xref: watmath net.micro:13569 net.arch:2424

> If the
> system has an intelligent disk controller, DMA transfer, and interrupt
> driven communication, then it doesn't have to stop/suspend the (slow)
> communications I/O in order to rev up the (slow) disk and write a sector.
> 
> DMA, interrrupts, and intelligent controllers are all available on well
> integrated chip sets... even the 4-year old IBM PCs and clones have them.
> The fact that low-end systems (particularly Apple ][) do not have these 
> capabilities often means that quality software is not available to do
> functions that might require concurrent I/O.  I think that's a shame.

While the Apple is being used in scientific laboratories world-wide,
I find the lack of concurrent disk I/O painful.  I would like to 
be able to stream incoming data directly to disk, as is possible 
on the IBM PC.  Instead, I have to use a RAM card as a psuedo-disk, stop
collecting data for a few seconds, save the data as a file, and then continue.
Since I collect 400 two-byte values per second, the RAM files up rather 
quickly.  Except for this, the Apple is a good laboratory system!
-- 
====================================================================
David Robins, M.D. 
Smith-Kettlewell Institute of Visual Sciences
2232 Webster St; San Francisco CA 94115
415/561-1705
			{ihnp4,qantel,dual}!ptsfa!ski!dr

The opinions expressed herein do not reflect the opinion of the Institute!