[KLUG Members] Re: partition check? -- You've got ATA DMA timeout issues ...

[Bryan J. Smith]

On Fri, 2002-05-10 at 22:03, Bill Katsma wrote:
> What is PIO?  and what is the disadvantage to doing this?

Programmed I/O.  It means the CPU controls the disk-to-memory I/O
instead of the disk directly transfering to memory (DMA -- direct memory
access).  It eats up CPU, but notebook HDs aren't know for their killer
transfer rates.  As long as you're not using it as a server, it won't
hurt you too bad.  In fact, it'll get rid of those "stalls" when the DMA
times out -- so it might actually improve performance.

On Fri, 2002-05-10 at 22:05, Bill Katsma wrote:
> Unfortunitally this is compaq laptop computer and ever since I
> loaded Linux I can no longer get into the BIOS configuration.

Hence why you should _never_ touch unknown partitions on a laptop's disk
drive.  ;-P

> From what I have read Compaq is known for buting there BIOS
> on the HD. (If that makes any sence)

Most laptops have weird configurations.  Same deal with select desktops,
like Compaq's.

I think you can pass a kernel parameter to LILO to prevent DMA.  You can
also recompile the kernel to NOT use DMA by default (unless you
specifically enable it via hdparm).

Otherwise, modify /etc/rc.d/rc.sysinit (RedHat) and put this line at the
top:
   /sbin/hdparm -d0 -u0 /dev/hda

Although the latter might not happen until later, after the partition
check.  BTW, what chipset is on the mainboard?

-- Bryan

-- 
The US government could be 100x more effective, and 1/100th the
Constitutional worry, if it dictated its policy to Microsoft as
THE MAJOR CUSTOMER it is, and not THE REGULATOR it fails to be.
---------------------------------------------------------------
Bryan J. Smith, SmithConcepts, Inc.   mailto:b.j.smith@ieee.org
Engineers and IT Professionals     http://www.SmithConcepts.com