--On Wednesday, June 02, 2004 18:48:46 -0400 Jon LaBadie <jon AT jgcomp DOT 
com> wrote:

> On Wed, Jun 02, 2004 at 04:21:35PM -0600, Glenn English wrote:
>> On Wed, 2004-06-02 at 14:12, Gene Heskett wrote:
>> 
>> > Any current ide drive can do 30+ Mb/sec if left 
>> > alone by other tasks, often quite a ways on the + side.
>> 
>> Is that just a burst out of the cache, or can they read dis-contiguous
>> files, seek around to other files, wait for latency, and write all at
>> the same time that fast? Or even half that fast? If so, and if Linux and
>> Intel's IDE controllers lose another 25% moving bits around, it'd still
>> be comfortably faster than the tape drive. I think I may have something
>> horribly misconfigured.
> 
> On Solaris x86, one thing that terribly degrades IDE disk
> performance is if the driver does not use dma but uses pio mode.
> There are even reports of diagnostic tools saying the drive is
> using dma, but digging deeper determines that pio mode is in use.
> 
> I know not how to check or configure the HD driver on linux,
> but it might be something to check.

If it's linux, try using hdparm to verify the modes and speed of your
disk.  Like Jon says, a good drive can have terrible performance if
it is running in the wrong mode.
   Also, make sure your kernel is using the correct chipset driver
for your IDE controller.  On a machine at home I replaced the
motherboard and my disk speeds dropped to under 2MB/sec.  I finally
figured out that since I had a different controller than the one I had
compiled in support for, the kernel had dropeed back to generic IDE
support.  Rebuilding the kernel with the proper driver made an over 10X
performance boost.

Frank

> 
> -- 
> Jon H. LaBadie                  jon AT jgcomp DOT com
>  JG Computing
>  4455 Province Line Road        (609) 252-0159
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