man > hd(4)

hd(4)                                 Kernel Interfaces Manual                                 hd(4)

NAME
       hd - MFM/IDE hard disk devices

DESCRIPTION
       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  is
       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.   How‐
       ever,  partition numbers 1–4 are given to the four partitions described in the MBR (the "pri‐
       mary" partitions), regardless of whether they are unused or extended.  Thus, the first  logi‐
       cal  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*

FILES
       /dev/hd*

SEE ALSO
       chown(1), mknod(1), sd(4), mount(8)

Linux man-pages 6.7                          2023-10-31                                        hd(4)