Roy P. Turner (
Thu, 18 Dec 1997 01:02:05 -0600

In message <>, mlord writes:
> The 32-bit IO and multcount work only for PIO, not DMA.
> On some drives (?), multcount might even slow down DMA,
> though there is no evidence to support this theory.
> Neither of these buys anything when DMA is used.

Ok, I just went on the hdparm man page which doesn't really say much about
when certain settings should be used. I just turned on everything the
man page indicated would increase performance and none of it ever caused
any problems. I turned off multcount and 32 bit I/O since I am using
DMA mode 2 on my non UDMA drives. Thanks for the further information.

> The write-caching can be turned on ("hdparm -W1") to speed up writing,
> but one must be careful to turn it off again at system shutdown,
> to ensure the cache is flushed before reset or poweroff.

If turn off UDMA in the bios for this drive, I am able to use write
caching without a hitch. If I enable UDMA for this drive in the bios,
write caching still causes irq timeouts. I do turn it off at shutdown
as I saw advice to do so earlier on the list. Perhaps the hdparm man
page should say something about this?

> Mmm.. not sure what the issue might be.
> See if things are any different with 2.1.73, when it appears.

Deal. I'll keep write caching off for now and let you know how it goes
when 2.1.73 comes out.