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From: eric@ulysses.homer.nj.att.com (Eric Lavitsky)
Newsgroups: comp.sys.amiga
Subject: Re: Hard disk through parallel port
Message-ID: <1527@ulysses.homer.nj.att.com>
Date: Wed, 17-Dec-86 10:59:47 EST
Article-I.D.: ulysses.1527
Posted: Wed Dec 17 10:59:47 1986
Date-Received: Thu, 18-Dec-86 02:50:24 EST
References: <634@hp-sdd.HP.COM> <1121@cbmvax.cbmvax.cbm.UUCP>
Reply-To: eric@ulysses.UUCP (Eric Lavitsky)
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 18
Keywords: hard disks, DMA, AmigaDOS

>George Robbins (cbmvax!grr) Writes:
>Well, since there is no DMA support available for the Parallel Port, the
>actual data transfer part of the disk activity will be slower than a DMA
>type disk controller attached to the Expansion Bus.

A bit of clarification here: George is correct, but: The only thing DMA
really buys you on the Amiga currently, is the fact that data trasnfers
don't interrupt the CPU. The maximum *actual* throughput for current DMA 
vs. non DMA disks is currently limited by AmigaDOS, which can only chug 
through about 35K/Sec. So, a disk on the parallel port, if designed correctly,
will get you at least close to that limit and a DMA disk cannot surpass
that limit (at least not the ones that currently exist). Of course, if
you're not using AmigaDOS, that's another story...

Has anyone used the disk benchmark recently posted by Rick Spanbauer on
some of the popular Amiga hard disks?

Eric