Date: Wed, 22 Mar 1995 20:19:58 +1000 From: Bruce Evans <bde@zeta.org.au> To: hasty@star-gate.com, phk@ref.tfs.com Cc: faq@FreeBSD.org, hackers@FreeBSD.org Subject: Re: Why IDE is bad Message-ID: <199503221019.UAA09977@godzilla.zeta.org.au>
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>I don't think you will find many ide's faster than the WDC, I know >it can run faster on a better IDE-controller, but this is a fairly >standard IDE controller so it's a good indication. >And yes, but FreeBSD doesn't support DMA in IDE (yet ?)... The WDC specs that I've seen show DMA speeds slightly slower than IDE speeds so DMA may not be worth using. I forgot to think about the possibility of overlapping DMA cycles with cpu cycles in my previous mail about this. I reported a 28% slowdown for counting to 100000000. The cpu mostly executes 2 instructions in a loop. There should be few bus accesses to slow the cpu down. Maybe busmastering is broken. Bruce
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