About.com: Speed up your IDE drives

“If you’re using a recent DMA, UDMA-33 or even UDMA-66 IDE
drive and motherboard and feel that under Linux, disk access seems
slow compared to Windows, you may be right. In some situations,
Linux doesn’t automatically enable DMA for IDE hard drives. At
times, this is because the driver for your particular hardware
isn’t quite “stable” but it’s often simply because Linux
programmers want to allow you to enable DMA yourself if you choose
to do so.”

“Before “playing” with your hard drive’s DMA or multi-sector
settings, be sure to back up all of your important data. There is a
chance, albeit a small one, that enabling DMA can cause problems
with your hardware and generate filesystem corruption. In such
cases, you’ll want to have backups of important data available on a
separate disk or on removable media.”

“Once your data is backed up, you can see what your current hard
drive settings look like by calling the hdparm program as root and
specifying your hard drive’s device node as an argument…
Supplying hdparm with no arguments other than the device node will
print information on the device and its current configuration.”

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