Basic hardware configuration

Root hard disk bootstrings

The hd bootstring overrides the default search sequence used by the hd driver to determine the root disk. The syntax of the bootstring is:

hd=driver

where driver is the disk driver prefix.

Valid driver prefixes are:

esdi: ESDI disk controller on MCA machines
ida0: Compaq IDA controller
st506: ST506 disk controller on MCA machines
Sdsk: generic SCSI disk driver for all machine architectures
wd0: generic Western Digital WD1010 disk driver for controllers such as ESDI and IDE that present a ST506 interface on ISA and EISA machines

This bootstring is required by those controllers (such as some Compaq IDA and some SCSI host adapters) that appear to be WD1010-style controllers. By default, hd recognizes the wd driver before the Sdsk or ida drivers. This prevents these disks from being configured as the root disk.

To boot from a Compaq IDA drive, you would use the bootstring hd=ida0.

You should add this bootstring to the definition of DEFBOOTSTR in the file /etc/default/boot so that the system uses the correct root disk configuration when it boots.