2.4.18 kernels: no DMA w/ServerWorks LE chipsets

Josip Loncaric josip at icase.edu
Fri Aug 2 07:29:17 PDT 2002

Steven Timm wrote:
> You can set the DMA to be on at startup by using the file
> /etc/sysconfig/harddisks  --that is what we do.
> we set the DMA on the system disk to MWDMA mode 2 (hdparm -X34).

Since plain "-d1" locked up one of our systems using ServerWorks OSB4
chipset, we now request MWDMA mode 2 using the following lines in


and the disk read performance has improved from ~4 MB/s to ~15 MB/s
without immediate lockups.  Long term stability under load has yet to be

Our drives are mostly IBM, but there are a couple Maxtor/Quantum
models.  With some luck, they may be less sensitive to the ServerWorks
OSB4 hardware bug...

Thanks for the suggestion,

Dr. Josip Loncaric, Research Fellow               mailto:josip at icase.edu
ICASE, Mail Stop 132C           PGP key at http://www.icase.edu./~josip/
NASA Langley Research Center             mailto:j.loncaric at larc.nasa.gov
Hampton, VA 23681-2199, USA    Tel. +1 757 864-2192  Fax +1 757 864-6134

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