Ever thought why your disk takes ages to move that all important film your private folder? May be Linux utility hdparm can help you. hdparm is a utility which allows you to view and change certain hard disk parameters whether it be SATA or PATA. Here are some useful commands which you can use to probe the status of your drive and find tune it.
Viewing hard drive information
* hdparm -I /dev/sda
Viewing hard drive performance
* hdparm -Tt /dev/sda
-T = Checks the how quickly data can be passed between the processor, memory, and disk cache
-t = Reads continuously from the hard disk without reading previously cached data. This gives an indication of the speed at which Linux can read sequential data from the disk
Tuning the drive
* hdparm -W1 /dev/sda (Turns write cache on. Use -W0 to set it to off)
* hdparm -A1 /dev/sda (Turns read ahead cache on. Use -A0 to set it to off)
* hdparm -a[n] /dev/sda (Turns read ahead cache on with n KB read ahead)
* hdparm -d1 [mode-option] /dev/sda (Turns DMA on with specified mode)
pio0 -X08 Programmed I/O
mdma0 -X32 Multiword DMA
udma0 -X64 Ultra DMA
* hdparm -m[n] /dev/sda (Turns on mulisector I/O mode in which more than one sector can be transferred within one interrupt. n is the number of sectors. Typical 8,16 etc.)
Try experiment with these options and then measure disk performance with every change. You may be surprised with some improvements. But remember some setting may be too aggressive to your hard-drive. So think twice if you are setting too aggressive values to increase the performance.
Making things permanent
These changes will only be available in the current session. Modify /etc/hdparm.conf with these options to make the changes permanent across reboots.