DISKPART(8)

NAME
diskpart - calculate default disk partition sizes

SYNOPSIS
/etc/diskpart [ -p ] [ -d ] disk-type

DESCRIPTION
Diskpart is used to calculate the disk partition sizes based on the default rules used at the University of California at Berkeley. These values are to be used on an advisory basis only; your actual needs may dictate different values. 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 description file /etc/disktab is generated; see disktab(5). Diskpart assumes that the disk is formatted with the DEC standard 144 format. Space is always 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 sufficient 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 give 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, including the space reserved for the bad sector forwarding table. 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, and may result in unsatisfactory layouts.

When using the -d flag, alternate disk names are not included in the output.

Diskpart only understands how to handle drives formatted via the DEC standard 144 format. For other formats, use /etc/disktab for partition information.