hd — MFM/IDE hard disk devices
The hd* devices are block
devices to access MFM/IDE hard disk drives in raw mode. The
master drive on the primary IDE controller (major device
number 3) is hda; the slave
drive is hdb. The master drive
of the second controller (major device number 22) is
hdc and the slave hdd.
General IDE block device names have the form hdX, or
hdXP, where X
is a letter denoting the physical drive, and P is a number denoting the partition on
that physical drive. The first form, hdX, is used to address the
whole drive. Partition numbers are assigned in the order the
partitions are discovered, and only nonempty, nonextended
partitions get a number. However, partition numbers 1-4 are
given to the four partitions described in the MBR (the
"primary" partitions), regardless of whether they are unused
or extended. Thus, the first logical partition will be
hdX5. Both DOS-type partitioning
and BSD-disklabel partitioning are supported. You can have at
most 63 partitions on an IDE disk.
For example, /dev/hda refers
to all of the first IDE drive in the system; and /dev/hdb3 refers to the third DOS "primary"
partition on the second one.
They are typically created by:
mknod −m 660 /dev/hda b 3 0
mknod −m 660 /dev/hda1 b 3 1
mknod −m 660 /dev/hda2 b 3 2
...
mknod −m 660 /dev/hda8 b 3 8
mknod −m 660 /dev/hdb b 3 64
mknod −m 660 /dev/hdb1 b 3 65
mknod −m 660 /dev/hdb2 b 3 66
...
mknod −m 660 /dev/hdb8 b 3 72
chown root:disk /dev/hd*