Subject: Re: Is Ultra/100 really supported?
To: None <>
From: Wolfgang Rupprecht <>
List: current-users
Date: 12/11/2000 12:17:46
> I tried hard coding the flags (0d00) on wd0 to force Ultra/100.
> Indeed, the dmesg then showed Ultra/100 everywhere, but the time to
> compile userland (59 mins) was nearly identical (within seconds) to
> the case where dmesg is as above, so I am not sure I believe anything
> other than the messages really changed.

Ultra/100 is a win if you have multiple disks on the ATA bus or if you
have a big fat raid pretending to be a single disk.  It just isn't
going to do much for you unless you have a bottleneck at your ATA bus.

The limiting speed if you have a single disk is still going to be
dominated by the seek time, the rotational latency, and the data-rate
at the head.  The delay to get stuff across the ATA bus is essentially
lost in the noise.

       Wolfgang Rupprecht <>
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