Re: Absolutely horrid IDE performance...

Rik van Riel (H.H.vanRiel@phys.uu.nl)
Thu, 26 Nov 1998 11:17:23 +0100 (CET)


On Wed, 25 Nov 1998, Nate Thompson wrote:
> Mark Lord Said:
> > Ooops.. wait a minute.. you said:
> >
> > >ide: i82371 PIIX (Triton) on PCI bus 0 function 57
> >
> > The Intel PIIX chip does not support UDMA.
>
> Ummm..... What? Yes it does. Either that or I have been horribly
> lied to by everything I've seen elsewhere?!?!?!

My board doesn't support UDMA (AFAIK) because it predates
the UDMA standard by quite a while:

Bus 0, device 7, function 1:
IDE interface: Intel 82371FB PIIX IDE (rev 2).
Medium devsel. Fast back-to-back capable. Master Capable. Latency=32.
I/O at 0x3000 [0x3001].

If you happen to have a higher revision (3, 4?) your board
might support UDMA though... I have heard some rumours
about revision 4 supporting UDMA and lower revisions not,
but my memory regarding this is too foggy to know for sure :)

I can use PIO mode 4 and DMA mode 2 though... Fast enough
for my needs since my high-performance files are on SCSI
anyway.

Btw, I discovered just today that my 1995 Quantum Trailblazer
can run at 2.96 MB/s. I've been running it in standard mode
(-c1 -d1) for years with worse performance. It even is faster
than the 6.4GB Maxtor I bought (cheaply) last friday :)
My 1989 Maxtor SCSI disk gets half the performance while my
WD Enterprise delivers 5 to 6.5 MB/s to my system.

I guess this makes a pretty decent I/O subsystem for a P100
with 72 megs of RAM...

cheers,

Rik -- now completely used to dvorak kbd layout...
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