Red Hat

As root, edit /etc/sysconfig/harddisks:

USE_DMA=1
MULTIPLE_IO=16
EIDE_32BIT=1
LOOKAHEAD=1
EXTRA_PARMS= hdparm ?u1 /dev/hda

Debian

As root, add to /etc/init.d/local:

#! /bin/sh
hdparm -c3 -d1 -u1 -m16 /dev/hda