Hdparm
From S23Wiki
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"
