DISKTAB(5) - File Formats Manual #

DISKTAB(5) - File Formats Manual

NAME #

disktab - disk description file

DESCRIPTION #

disktab is a simple database which 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(5) terminal database. Entries in disktab 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 “|” 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**  
dt        str     Type of controller (e.g., 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 (default: ns\*nt).  
su        num     Number of sectors per unit (default: sc\*nc).  
se        num     Sector size in bytes (default:
`DEV_BSIZE`).

ba        num     Block size for partition
"a"
(bytes).  
bd        num     Block size for partition
"d"
(bytes).  
be        num     Block size for partition
"e"
(bytes).  
\[...]               
bp        num     Block size for partition
"p"
(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).  
\[...]               
fp        num     Fragment size for partition
"p"
(bytes).

oa        num     Offset of partition
"a"
(sectors).  
ob        num     Offset of partition
"b"
(sectors).  
oc        num     Offset of partition
"c"
(sectors).  
\[...]               
op        num     Offset of partition
"p"
(sectors).

pa        num     Size of partition
"a"
(sectors).  
pb        num     Size of partition
"b"
(sectors).  
pc        num     Size of partition
"c"
(sectors).  
\[...]               
pp        num     Size of partition
"p"
(sectors).

ta        str     Type of partition
"a"
(4.2BSD, swap, etc.).  
tb        str     Type of partition
"b".  
tc        str     Type of partition
"c".  
\[...]               
tp        str     Type of partition
"p".

FILES #

/etc/disktab

SEE ALSO #

getdiskbyname(3), disklabel(5), disklabel(8), newfs(8)

HISTORY #

The disktab description file appeared in 4.2BSD.

OpenBSD 7.5 - November 7, 2022