hdparm is used in Linux for setting harddisk options.
To view current settings, simply run: hdparm /dev/hda (or /hdb, /hdc, etc.)
-c1 enables 32-bit I/O -d1 enables DMA -X66 enables ATA/33
PIO mode Switch Burst Rate 0 -X08 3.3MB/sec 1 -X09 5.2MB/sec 2 -X10 8.3MB/sec 3 -X11 11.1MB/sec 4 -X12 16.7MB/sec
MW DMA mode Switch Burst Rate 0 -X32 4.2MB/sec 1 -X33 13.3MB/sec 2 -X34 16.6MB/sec
UDMA mode Switch Burst Rate 2 (ATA/33) -X66 33MB/sec 4 (ATA/66) -X68 66MB/sec 5 (ATA/100) -X69 100MB/sec
Red Hat uses /etc/rc.sysinit to call scripts /etc/sysconfig/harddiskhda, /etc/sysconfig/harddiskhdb, etc. to run hdparm upon boot.
File: /etc/sysconfig/harddiskhda:
USE_DMA=1
EIDE_32BIT=1
To enable DMA during boot, add the following line to your lilo.conf file:
append = "ide0=dma"