# phpman > man > hd(4)

[HD(4)](https://www.chedong.com/phpMan.php/man/HD/4/markdown)                                 Linux Programmer's Manual                                [HD(4)](https://www.chedong.com/phpMan.php/man/HD/4/markdown)



## 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 **hd**_X_, or **hd**_XP_, where _X_ is a letter  denoting  the
       physical  drive,  and _P_ is a number denoting the partition on that physical drive.  The first
       form, **hd**_X_, 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 **hd**_X_**5**.  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)](https://www.chedong.com/phpMan.php/man/chown/1/markdown), [**mknod**(1)](https://www.chedong.com/phpMan.php/man/mknod/1/markdown), [**sd**(4)](https://www.chedong.com/phpMan.php/man/sd/4/markdown), [**mount**(8)](https://www.chedong.com/phpMan.php/man/mount/8/markdown)

## COLOPHON
       This page is part of release 5.10 of the Linux  _man-pages_  project.   A  description  of  the
       project,  information about reporting bugs, and the latest version of this page, can be found
       at <https://www.kernel.org/doc/man-pages/>.



Linux                                        2017-09-15                                        [HD(4)](https://www.chedong.com/phpMan.php/man/HD/4/markdown)