Re: IDE-DMA strangeness (another one)

Mark Gray (
02 Dec 1998 06:25:27 -0500

> > Rik van Riel <> writes:
> > > I've just moved my IDE disks around, taking out an old
> > > disk and moving my new 6.4GB disk from hdd to hda.
> > With this move I saw in improvement (hdparm -t) from 3
> > to 8.4 (!) MB/second... Now I wonder what kind of bug
> On 1 Dec 1998, Mark Gray wrote:
> > Some motherboards use a crippled controller for ide1 in the belief
> > that it will only be used for cdroms.

"Andre M. Hedrick" <hedrick@Astro.Dyer.Vanderbilt.Edu> writes:
> That is usually because of lazy BIOS writers/hackers (ass)(u)(me)
> "Nobody will use more than two hardrives"

He didn't mention which motherboard he was using in that particular
letter -- I just wanted to point out that some older motherboards
(such as a 60Mhz pentium Intel Mercury chipset based one I used to
have) would use a PCI controller for ide0 and a slower controller such
as the 82091AA Advanced Integrated Peripheral "Super Controller" for
ide1 and everything else (ide, floppy, 2 uarts, parallel port, game
port etc, etc.) (This was a safe way to use CMD 640's once the bug
was discovered it seems.) From your letters you appear to have kept
track of what motherboard he was talking about ... so "never mind" :-)

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