disktab(4) — File Formats
NAME
disktab − Disk description file
SYNOPSIS
#include <sys/disklabel.h>
DESCRIPTION
The disktab database describes disk geometries and disk partition characteristics. It is used to initialize the disk label on the disk. The format is patterned after the termcap terminal database. Entries in a disktab file consist of a number of : (colon) separated fields. The first entry for each disk gives the names which are known for the disk, separated by | (vertical bar) characters. The last name given should be a long name fully identifying the disk.
The following list indicates the normal values stored for each disk entry:
| Name | Type | Description |
| ty | str | Type of disk (for example, removable, winchester) |
| dt | str | Type of controller (for example, SMD, ESDI, floppy) |
| ns | num | Number of sectors per track |
| nt | num | Number of tracks per cylinder |
| nc | num | Total number of cylinders on the disk |
| sc | num | Number of sectors per cylinder, nc∗nt default |
| su | num | Number of sectors per unit, sc∗nc default |
| se | num | Sector size in bytes, DEV_BSIZE default |
| sf | bool | Controller supports bad144-style bad sector forwarding |
| rm | num | Rotation speed, rpm, default 3600 |
| sk | num | Sector skew per track, default 0 |
| cs | num | Sector skew per cylinder, default 0 |
| hs | num | Headswitch time, usec, default 0 |
| ts | num | One-cylinder seek time, usec, default 0 |
| il | num | Sector interleave (n:1), default 1 |
| d[0-4] | num | Drive-type-dependent parameters |
| bs | num | Boot block size, default BBSIZE |
| sb | num | Superblock size, default SBSIZE |
| ba | num | Block size for partition ‘a’ (bytes) |
| bd | num | Block size for partition ‘d’ (bytes) |
| be | num | Block size for partition ‘e’ (bytes) |
| bf | num | Block size for partition ‘f’ (bytes) |
| bg | num | Block size for partition ‘g’ (bytes) |
| bh | num | Block size for partition ‘h’ (bytes) |
| fa | num | Fragment size for partition ‘a’ (bytes) |
| fd | num | Fragment size for partition ‘d’ (bytes) |
| fe | num | Fragment size for partition ‘e’ (bytes) |
| ff | num | Fragment size for partition ‘f’ (bytes) |
| fg | num | Fragment size for partition ‘g’ (bytes) |
| fh | num | Fragment size for partition ‘h’ (bytes) |
| oa | num | Offset of partition ‘a’ in sectors |
| ob | num | Offset of partition ‘b’ in sectors |
| oc | num | Offset of partition ‘c’ in sectors |
| od | num | Offset of partition ‘d’ in sectors |
| oe | num | Offset of partition ‘e’ in sectors |
| of | num | Offset of partition ‘f’ in sectors |
| og | num | Offset of partition ‘g’ in sectors |
| oh | num | Offset of partition ‘h’ in sectors |
| pa | num | Size of partition ‘a’ in sectors |
| pb | num | Size of partition ‘b’ in sectors |
| pc | num | Size of partition ‘c’ in sectors |
| pd | num | Size of partition ‘d’ in sectors |
| pe | num | Size of partition ‘e’ in sectors |
| pf | num | Size of partition ‘f’ in sectors |
| pg | num | Size of partition ‘g’ in sectors |
| ph | num | Size of partition ‘h’ in sectors |
| ta | str | Partition type of partition ‘a’ (4.2BSD file system, swap, etc.) |
| tb | str | Partition type of partition ‘b’ |
| tc | str | Partition type of partition ‘c’ |
| td | str | Partition type of partition ‘d’ |
| te | str | Partition type of partition ‘e’ |
| tf | str | Partition type of partition ‘f’ |
| tg | str | Partition type of partition ‘g’ |
| th | str | Partition type of partition ‘h’ |
EXAMPLES
The following is an example disktab entry:
rz25|RZ25|DEC RZ25 Winchester:\
:ty=winchester:dt=SCSI:ns#62:nt#9:nc#1492:\
:oa#0:pa#131072:ba#8192:fa#1024:\
:ob#131072:pb#262144:bb#8192:fb#1024:\
:oc#0:pc#832527:bc#8192:fc#1024:\
:od#393216:pd#146437:bd#8192:fd#1024:\
:oe#539656:pe#146437:be#8192:fe#1024:\
:of#686096:pf#146437:bf#8192:ff#1024:\
:og#393216:pg#439311:bg#8192:fg#1024:\
:oh#0:ph#0:bh#8192:fh#1024:
FILES
/etc/disktab
SEE ALSO
Functions: getdiskbyname(3)
Files: disklabel(4)
Commands: disklabel(8), newfs(8)