DISKPART(8) System Manager's Manual DISKPART(8)
diskpart - calculate default disk partition sizes
/etc/diskpart [ -p ] [ -d ] disk-type
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
description file /etc/disktab is generated; c.f. disktab(5). Space is
always left in the last partition on the disk for a bad sector forward-
ing 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 sec-
tor 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.
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
Does not understand how to handle drives attached to a UDA50.
4th Berkeley Distribution 18 July 1983 DISKPART(8)