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 sec-
ond 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 par-
tition on that physical drive. The first form, hdX, is used to address
the whole drive. Partition numbers are assigned in the order the par-
titions are discovered, and only non-empty, non-extended partitions get
a number. However, partition numbers 1-4 are given to the four parti-
tions 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 partition-
ing 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 sys-
tem; and /dev/hdb3 refers to the third DOS "primary" partition on the
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*
chown(1), mknod(1), sd(4), mount(8)
This page is part of release 3.23 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 1992-12-17 HD(4)
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