1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)diskpart.8 8.1 (Berkeley) 06/06/93 7.\" 8.Dd 9.Dt DISKPART 8 10.Os BSD 4 11.Sh NAME 12.Nm diskpart 13.Nd calculate default disk partition sizes 14.Sh SYNOPSIS 15.Nm diskpart 16.Op Fl p 17.Op Fl d 18.Op Fl s Ar size 19.Ar disk-type 20.Sh DESCRIPTION 21.Nm Diskpart 22is used to calculate the disk partition sizes based on the 23default rules used at Berkeley. 24.Pp 25Available options and operands: 26.Bl -tag -width Fl 27.It Fl p 28Tables suitable for inclusion in a device driver 29are produced. 30.It Fl d 31An entry suitable for inclusion in the disk 32description file 33.Pa /etc/disktab 34is generated; for example, 35.Xr disktab 5 . 36.It Fl s Ar size 37The size of the disk may be limited to 38.Ar size 39with the 40.Fl s 41option. 42.El 43.Pp 44On disks that use 45.Xr bad144 8 46type of 47bad-sector forwarding, 48space is normally left in the last partition on the disk 49for a bad sector forwarding table, although this space 50is not reflected in the tables produced. The space reserved 51is one track for the replicated copies of the table and 52sufficient tracks to hold a pool of 126 sectors to which bad sectors 53are mapped. For more information, see 54.Xr bad144 8 . 55The 56.Fl s 57option is intended for other controllers which reserve some space at the end 58of the disk for bad-sector replacements or other control areas, 59even if not a multiple of cylinders. 60.Pp 61The disk partition sizes are based on the total amount of 62space on the disk as given in the table below (all values 63are supplied in units of sectors). The 64.Ql c 65partition 66is, by convention, used to access the entire physical disk. 67The device driver tables include 68the space reserved for the bad sector forwarding table in the 69.Ql c 70partition; 71those used in the disktab and default formats exclude reserved tracks. 72In normal operation, either the 73.Ql g 74partition is used, or the 75.Ql d , 76.Ql e , 77and 78.Ql f 79partitions are used. The 80.Ql g 81and 82.Ql f 83partitions 84are variable-sized, occupying whatever space remains after allocation 85of the fixed sized partitions. 86If the disk is smaller than 20 Megabytes, then 87.Nm diskpart 88aborts with the message 89.Dq Li disk too small, calculate by hand . 90.Bl -column Partition 20-60\ MB 61-205\ MB 206-355\ MB 356+\ MB 91Partition 20-60 MB 61-205 MB 206-355 MB 356+ MB 92a 15884 15884 15884 15884 93b 10032 33440 33440 66880 94d 15884 15884 15884 15884 95e unused 55936 55936 307200 96h unused unused 291346 291346 97.El 98.Pp 99If an unknown disk type is specified, 100.Nm diskpart 101will prompt for the required disk geometry information. 102.Sh SEE ALSO 103.Xr disktab 5 , 104.Xr bad144 8 105.Sh BUGS 106Most default partition sizes are based on historical artifacts 107(like the RP06), and may result in unsatisfactory layouts. 108.Pp 109When using the 110.Fl d 111flag, alternate disk names are not included 112in the output. 113.Sh HISTORY 114The 115.Nm 116command appeared in 117.Bx 4.2 . 118