Tom Livingston wrote:
> I have a system with 12 udma disks, and in practice it's been a nightmare.
> Once you start using more than two interfaces the auto-tuning code in the
> kernel ceases to work correctly, so you have to "tune up" each disk after
> boot. Also, udma-66 has a cable length limit of 18", which can make it
hard
> to place disks
speaking of "tuning up", how do you set DMA mode 3 and 4 on an U-ATA-66
disk? I have a RAID5 array on 4 WD 20.4GB U-ATA-66 drives (with all
specified hardware and bios requirements for UDMA-66 support). I have
installed the general UDMA patch (and hdparm v3.5) and recompiled the 2.2.10
kernel with the "UDMA-66 (Dangerous!)" option enabled (as well as having DMA
defaulted, and support for my VIA-VT82C686A chipset (the patch was written
to support the previous version (VIA-VT82C586A) but it seems to print the
parameters in /proc/ide/via okay.)). In short, I think everything is set up
so I _should_ have DMA mode 3&4 running, but when I do an 'hdparm -i
/dev/hdX' I get 'maxDMA=2(fast)'.
What do I need to do to enable full UDMA-66 support? What are some tuning
options that would enable this?
Thanks!
-ck
_____________________________________________________
Sherlock Holmes and Dr. Watson went on a camping trip. As they lay down
for the night, Holmes said: "Watson, look up at the sky and tell me what
you see."
Watson replied, "I see millions and millions of stars."
"And what can you deduce from that?" inquired Holmes.
"Astronomically," began Watson," it implies that there are millions of
galaxies, each with billions of stars, and that if even 1% of them have
planets, and only 1% of those have planets like earth then surely there
must be other intelligent beings out there like ourselves."
"Theologically," continued Watson, "it tells me that God is great and that
we are small and insignificant. And meteorologically it tells me that we
will have a beautiful cloud-free day tomorrow. What does it tell you?"
"Somebody stole our tent."
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