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From: perry@well.UUCP (Perry S. Kivolowitz)
Newsgroups: comp.sys.amiga
Subject: Re: Disk Controllers
Message-ID: <2111@well.UUCP>
Date: Mon, 24-Nov-86 00:26:44 EST
Article-I.D.: well.2111
Posted: Mon Nov 24 00:26:44 1986
Date-Received: Mon, 24-Nov-86 22:05:28 EST
References: <2043@well.UUCP> <758@ulowell.UUCP> <1986Nov19.104846.321@utcs.uucp> <1242@masscomp.UUCP>
Organization: Whole Earth Lectronic Link, Sausalito, CA
Lines: 12
Summary: all those interrupts aren't necessary though...

In article <1242@masscomp.UUCP>, garyo@masscomp.UUCP (Gary Oberbrunner) writes:
> Most of this is true.  Normally, disk rate shouldn't be much improved
> by using DMA, since most of the time is spent seeking.  However, with a
> non-DMA controller the overhead during the actual transfer is MUCH higher,
> since the device must do CPU interrupts per byte transferred.  Thus not
> only is the transfer slowed by using the CPU, it's doubly slowed
> because other computation cannot proceed while all these interrupts are
> happening.

But the transfers don't  HAVE  TO  NECESSITATE (sp?) interrupts. The processor
in a tight loop will run competitively to the overhead of handling interrupts.
If you were to do a non dma driven disk controller, that is.