diskpart(8) [bsd man page]
DISKPART(8) System Manager's Manual DISKPART(8) NAME
diskpart - calculate default disk partition sizes SYNOPSIS
/usr/sbin/diskpart [ -p ] [ -d ] disk-type DESCRIPTION
Diskpart is used to calculate the disk partition sizes based on the default rules used at Berkeley. If the -p option is supplied, tables suitable for inclusion in a device driver are produced. If the -d option is supplied, an entry suitable for inclusion in the disk descrip- tion file /etc/disktab is generated; c.f. disktab(5). On disks that use bad144-style bad-sector forwarding, space is left in the last partition on the disk for a bad sector forwarding table. The space reserved is one track for the replicated copies of the table and suffi- cient tracks to hold a pool of 126 sectors to which bad sectors are mapped. For more information, see bad144(8). The disk partition sizes are based on the total amount of space on the disk as given in the table below (all values are supplied in units of 512 byte sectors). The `c' partition is, by convention, used to access the entire physical disk. The device driver tables include the space reserved for the bad sector forwarding table in the `c' partition; those used in the disktab and default formats exclude reserved tracks. In normal operation, either the `g' partition is used, or the `d', `e', and `f' partitions are used. The `g' and `f' partitions are variable-sized, occupying whatever space remains after allocation of the fixed sized partitions. If the disk is smaller than 20 Megabytes, then diskpart aborts with the message ``disk too small, calculate by hand''. Partition 20-60 MB 61-205 MB 206-355 MB 356+ MB a 15884 15884 15884 15884 b 10032 33440 33440 66880 d 15884 15884 15884 15884 e unused 55936 55936 307200 h unused unused 291346 291346 If an unknown disk type is specified, diskpart will prompt for the required disk geometry information. SEE ALSO
disktab(5), bad144(8) BUGS
Certain default partition sizes are based on historical artifacts (e.g. RP06), and may result in unsatisfactory layouts. When using the -d flag, alternate disk names are not included in the output. 4th Berkeley Distribution November 17, 1996 DISKPART(8)
Check Out this Related Man Page
disktab(4) Kernel Interfaces Manual disktab(4) 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: Type Description str Type of disk (for example, removable, win- chester) str Type of controller (for example, SMD, ESDI, floppy) num Number of sectors per track num Number of tracks per cylinder num Total number of cylinders on the disk num Number of sectors per cylinder, nc*nt default num Number of sectors per unit, sc*nc default num Sector size in bytes, DEV_BSIZE default bool Controller supports bad144-style bad sector forwarding num Rotation speed, rpm, default 3600 num Sector skew per track, default 0 num Sector skew per cylinder, default 0 num Headswitch time, usec, default 0 num One-cylinder seek time, usec, default 0 num Sector interleave (n:1), default 1 num Drive-type-dependent parameters num Boot block size, default BBSIZE num Superblock size, default SBSIZE num Block size for partition `a' (bytes) num Block size for partition `d' (bytes) num Block size for partition `e' (bytes) num Block size for partition `f' (bytes) num Block size for partition `g' (bytes) num Block size for partition `h' (bytes) num Fragment size for partition `a' (bytes) num Fragment size for partition `d' (bytes) num Fragment size for partition `e' (bytes) num Fragment size for partition `f' (bytes) num Fragment size for partition `g' (bytes) num Fragment size for partition `h' (bytes) num Offset of partition `a' in sectors num Offset of partition `b' in sectors num Offset of partition `c' in sectors num Offset of partition `d' in sectors num Offset of partition `e' in sectors num Offset of partition `f' in sectors num Offset of partition `g' in sectors num Offset of partition `h' in sectors num Size of partition `a' in sectors num Size of partition `b' in sectors num Size of partition `c' in sectors num Size of partition `d' in sectors num Size of partition `e' in sectors num Size of partition `f' in sectors num Size of partition `g' in sectors num Size of partition `h' in sectors str Partition type of partition `a' (4.2BSD file system, swap, etc.) str Partition type of partition `b' str Partition type of partition `c' str Parti- tion type of partition `d' str Partition type of partition `e' str Partition type of partition `f' str Partition type of partition `g' 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 RELATED INFORMATION
Functions: getdiskbyname(3) Files: disklabel(4) Commands: disklabel(8), newfs(8) delim off disktab(4)