1.\" Copyright (c) 1987, 1988, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Symmetric Computer Systems. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 4. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)disklabel.8 8.2 (Berkeley) 4/19/94 32.\" $FreeBSD$ 33.\" 34.Dd October 1, 2013 35.Dt BSDLABEL 8 36.Os 37.Sh NAME 38.Nm bsdlabel 39.Nd read and write BSD label 40.Sh SYNOPSIS 41.Nm 42.Op Fl A 43.Ar disk | Fl f Ar file 44.Nm 45.Fl w 46.Op Fl \&An 47.Op Fl B Op Fl b Ar boot 48.Op Fl m Ar machine 49.Ar disk | Fl f Ar file 50.Op Ar type 51.Nm 52.Fl e 53.Op Fl \&An 54.Op Fl B Op Fl b Ar boot 55.Op Fl m Ar machine 56.Ar disk | Fl f Ar file 57.Nm 58.Fl R 59.Op Fl \&An 60.Op Fl B Op Fl b Ar boot 61.Op Fl m Ar machine 62.Op Fl f 63.Ar disk | Fl f Ar file 64.Ar protofile 65.Sh DESCRIPTION 66The 67.Nm 68utility 69installs, examines or modifies the 70.Bx 71label on a disk partition, or on a file containing a partition image. 72In addition, 73.Nm 74can install bootstrap code. 75.Ss Disk Device Name 76When specifying the device (i.e., when the 77.Fl f 78option is not used), 79the 80.Pa /dev/ 81path prefix may be omitted; 82the 83.Nm 84utility will automatically prepend it. 85.Ss General Options 86The 87.Fl A 88option enables processing of the historical parts of the 89.Bx 90label. 91If the option is not given, suitable values are set for these fields. 92.Pp 93The 94.Fl f 95option tells 96.Nm 97that the program will operate on a file instead of a disk partition. 98.Pp 99The 100.Fl n 101option stops the 102.Nm 103program right before the disk would have been modified, and displays 104the result instead of writing it. 105.Pp 106The 107.Fl m Ar machine 108argument forces 109.Nm 110to use a layout suitable for a different architecture. 111Current valid values are 112.Cm i386 , amd64 , 113and 114.Cm pc98 . 115If this option is omitted, 116.Nm 117will use a layout suitable for the current machine. 118.Ss Reading the Disk Label 119To examine the label on a disk drive, use the form 120.Pp 121.Nm 122.Op Fl A 123.Op Fl m Ar machine 124.Ar disk 125.Pp 126.Ar disk 127represents the disk in question, and may be in the form 128.Pa da0 129or 130.Pa /dev/da0 . 131It will display the partition layout. 132.Ss Writing a Standard Label 133To write a standard label, use the form 134.Pp 135.Nm 136.Fl w 137.Op Fl \&An 138.Op Fl m Ar machine 139.Ar disk 140.Op Ar type 141.Pp 142If the drive 143.Ar type 144is specified, the entry of that name in the 145.Xr disktab 5 146file is used; otherwise, or if the type is specified as 'auto', a default 147layout is used. 148.Ss Editing an Existing Disk Label 149To edit an existing disk label, use the form 150.Pp 151.Nm 152.Fl e 153.Op Fl \&An 154.Op Fl m Ar machine 155.Ar disk 156.Pp 157This command opens the disk label in the default editor, and when the editor 158exits, the label is validated and if OK written to disk. 159.Ss Restoring a Disk Label From a File 160To restore a disk label from a file, use the form 161.Pp 162.Nm 163.Fl R 164.Op Fl \&An 165.Op Fl m Ar machine 166.Ar disk protofile 167.Pp 168The 169.Nm 170utility 171is capable of restoring a disk label that was previously saved in a file in 172.Tn ASCII 173format. 174The prototype file used to create the label should be in the same format as that 175produced when reading or editing a label. 176Comments are delimited by 177.Ql # 178and newline. 179.Ss Installing Bootstraps 180If the 181.Fl B 182option is specified, bootstrap code will be read from the file 183.Pa /boot/boot 184and written to the disk. 185The 186.Fl b Ar boot 187option allows a different file to be used. 188.Sh FILES 189.Bl -tag -width ".Pa /etc/disktab" -compact 190.It Pa /boot/boot 191Default boot image. 192.It Pa /etc/disktab 193Disk description file. 194.El 195.Sh SAVED FILE FORMAT 196The 197.Nm 198utility 199uses an 200.Tn ASCII 201version of the label when examining, editing, or restoring a disk 202label. 203The format is: 204.Bd -literal -offset 4n 205 2068 partitions: 207# size offset fstype [fsize bsize bps/cpg] 208 a: 81920 16 4.2BSD 2048 16384 5128 209 b: 1091994 81936 swap 210 c: 1173930 0 unused 0 0 # "raw" part, don't edit 211.Ed 212.Pp 213If the 214.Fl A 215option is specified, the format is: 216.Bd -literal -offset 4n 217# /dev/da1c: 218type: SCSI 219disk: da0s1 220label: 221flags: 222bytes/sector: 512 223sectors/track: 51 224tracks/cylinder: 19 225sectors/cylinder: 969 226cylinders: 1211 227sectors/unit: 1173930 228rpm: 3600 229interleave: 1 230trackskew: 0 231cylinderskew: 0 232headswitch: 0 # milliseconds 233track-to-track seek: 0 # milliseconds 234drivedata: 0 235 2368 partitions: 237# size offset fstype [fsize bsize bps/cpg] 238 a: 81920 16 4.2BSD 1024 8192 16 239 b: 160000 81936 swap 240 c: 1173930 0 unused 0 0 # "raw" part, don't edit 241.Ed 242.Pp 243Lines starting with a 244.Ql # 245mark are comments. 246.Pp 247The partition table can have up to 8 entries. 248It contains the following information: 249.Bl -tag -width indent 250.It Ar # 251The partition identifier is a single letter in the range 252.Ql a 253to 254.Ql h . 255By convention, partition 256.Ql c 257is reserved to describe the entire disk. 258.It Ar size 259The size of the partition in sectors, 260.Cm K 261(kilobytes - 1024), 262.Cm M 263(megabytes - 1024*1024), 264.Cm G 265(gigabytes - 1024*1024*1024), 266.Cm % 267(percentage of free space 268.Em after 269removing any fixed-size partitions other than partition 270.Ql c ) , 271or 272.Cm * 273(all remaining free space 274.Em after 275fixed-size and percentage partitions). 276For partition 277.Ql c , 278a size of 279.Cm * 280indicates the entire disk. 281Lowercase versions of suffixes 282.Cm K , M , 283and 284.Cm G 285are allowed. 286Size and suffix should be specified without any spaces between them. 287.Pp 288Example: 2097152, 1G, 1024M and 1048576K are all the same size 289(assuming 512-byte sectors). 290.It Ar offset 291The offset of the start of the partition from the beginning of the 292drive in sectors, or 293.Cm * 294to have 295.Nm 296calculate the correct offset to use (the end of the previous partition plus 297one, ignoring partition 298.Ql c ) . 299For partition 300.Ql c , 301.Cm * 302will be interpreted as an offset of 0. 303The first partition should start at offset 16, because the first 16 sectors are 304reserved for metadata. 305.It Ar fstype 306Describes the purpose of the partition. 307The above example shows all currently used partition types. 308For 309.Tn UFS 310file systems and 311.Xr ccd 4 312partitions, use type 313.Cm 4.2BSD . 314For Vinum drives, use type 315.Cm vinum . 316Other common types are 317.Cm swap 318and 319.Cm unused . 320By convention, partition 321.Ql c 322represents the entire slice and should be of type 323.Cm unused , 324though 325.Nm 326does not enforce this convention. 327The 328.Nm 329utility 330also knows about a number of other partition types, 331none of which are in current use. 332(See the definitions starting with 333.Dv FS_UNUSED 334in 335.In sys/disklabel.h 336for more details.) 337.It Ar fsize 338For 339.Cm 4.2BSD 340file systems only, the fragment size; see 341.Xr newfs 8 . 342.It Ar bsize 343For 344.Cm 4.2BSD 345file systems only, the block size; see 346.Xr newfs 8 . 347.It Ar bps/cpg 348For 349.Cm 4.2BSD 350file systems, the number of cylinders in a cylinder group; see 351.Xr newfs 8 . 352.El 353.Sh EXAMPLES 354Display the label for the first slice of the 355.Pa da0 356disk, as obtained via 357.Pa /dev/da0s1 : 358.Pp 359.Dl "bsdlabel da0s1" 360.Pp 361Save the in-core label for 362.Pa da0s1 363into the file 364.Pa savedlabel . 365This file can be used with the 366.Fl R 367option to restore the label at a later date: 368.Pp 369.Dl "bsdlabel da0s1 > savedlabel" 370.Pp 371Create a label for 372.Pa da0s1 : 373.Pp 374.Dl "bsdlabel -w /dev/da0s1" 375.Pp 376Read the label for 377.Pa da0s1 , 378edit it, and install the result: 379.Pp 380.Dl "bsdlabel -e da0s1" 381.Pp 382Read the on-disk label for 383.Pa da0s1 , 384edit it, and display what the new label would be (in sectors). 385It does 386.Em not 387install the new label either in-core or on-disk: 388.Pp 389.Dl "bsdlabel -e -n da0s1" 390.Pp 391Write a default label on 392.Pa da0s1 . 393Use another 394.Nm Fl e 395command to edit the 396partitioning and file system information: 397.Pp 398.Dl "bsdlabel -w da0s1" 399.Pp 400Restore the on-disk and in-core label for 401.Pa da0s1 402from information in 403.Pa savedlabel : 404.Pp 405.Dl "bsdlabel -R da0s1 savedlabel" 406.Pp 407Display what the label would be for 408.Pa da0s1 409using the partition layout in 410.Pa label_layout . 411This is useful for determining how much space would be allotted for various 412partitions with a labeling scheme using 413.Cm % Ns -based 414or 415.Cm * 416partition sizes: 417.Pp 418.Dl "bsdlabel -R -n da0s1 label_layout" 419.Pp 420Install a new bootstrap on 421.Pa da0s1 . 422The boot code comes from 423.Pa /boot/boot : 424.Pp 425.Dl "bsdlabel -B da0s1" 426.Pp 427Install a new label and bootstrap. 428The bootstrap code comes from the file 429.Pa newboot 430in the current working directory: 431.Pp 432.Dl "bsdlabel -w -B -b newboot /dev/da0s1" 433.Pp 434Completely wipe any prior information on the disk, creating a new bootable 435disk with a 436.Tn DOS 437partition table containing one slice, covering the whole disk. 438Initialize the label on this slice, 439then edit it. 440The 441.Xr dd 1 442commands are optional, but may be necessary for some 443.Tn BIOS Ns es 444to properly 445recognize the disk: 446.Bd -literal -offset indent 447dd if=/dev/zero of=/dev/da0 bs=512 count=32 448gpart create -s MBR da0 449gpart add -t freebsd da0 450gpart set -a active -i 1 da0 451gpart bootcode -b /boot/mbr da0 452dd if=/dev/zero of=/dev/da0s1 bs=512 count=32 453bsdlabel -w -B da0s1 454bsdlabel -e da0s1 455.Ed 456.Pp 457This is an example disk label that uses some of the new partition size types 458such as 459.Cm % , M , G , 460and 461.Cm * , 462which could be used as a source file for 463.Dq Li "bsdlabel -R ada0s1 new_label_file" : 464.Bd -literal -offset 4n 465# /dev/ada0s1: 466 4678 partitions: 468# size offset fstype [fsize bsize bps/cpg] 469 a: 400M 16 4.2BSD 4096 16384 75 # (Cyl. 0 - 812*) 470 b: 1G * swap 471 c: * * unused 472 e: 204800 * 4.2BSD 473 f: 5g * 4.2BSD 474 g: * * 4.2BSD 475.Ed 476.Sh DIAGNOSTICS 477The kernel device drivers will not allow the size of a disk partition 478to be decreased or the offset of a partition to be changed while it is open. 479.Sh COMPATIBILITY 480Due to the use of an 481.Vt uint32_t 482to store the number of sectors, 483.Bx 484labels are restricted to a maximum of 2^32-1 sectors. 485This usually means 2TB of disk space. 486Larger disks should be partitioned using another method such as 487.Xr gpart 8 . 488.Pp 489The various 490.Bx Ns s 491all use slightly different versions of 492.Bx 493labels and 494are not generally compatible. 495.Sh SEE ALSO 496.Xr ccd 4 , 497.Xr geom 4 , 498.Xr md 4 , 499.Xr disktab 5 , 500.Xr boot0cfg 8 , 501.Xr gpart 8 , 502.Xr newfs 8 503