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 December 29, 2006 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 , ia64 , pc98 , 113and 114.Cm alpha . 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 a default layout is used. 147.Ss Editing an Existing Disk Label 148To edit an existing disk label, use the form 149.Pp 150.Nm 151.Fl e 152.Op Fl \&An 153.Op Fl m Ar machine 154.Ar disk 155.Pp 156This command opens the disk label in the default editor, and when the editor 157exits, the label is validated and if OK written to disk. 158.Ss Restoring a Disk Label From a File 159To restore a disk label from a file, use the form 160.Pp 161.Nm 162.Fl R 163.Op Fl \&An 164.Op Fl m Ar machine 165.Ar disk protofile 166.Pp 167The 168.Nm 169utility 170is capable of restoring a disk label that was previously saved in a file in 171.Tn ASCII 172format. 173The prototype file used to create the label should be in the same format as that 174produced when reading or editing a label. 175Comments are delimited by 176.Ql # 177and newline. 178.Ss Installing Bootstraps 179If the 180.Fl B 181option is specified, bootstrap code will be read from the file 182.Pa /boot/boot 183and written to the disk. 184The 185.Fl b Ar boot 186option allows a different file to be used. 187.Sh FILES 188.Bl -tag -width ".Pa /etc/disktab" -compact 189.It Pa /boot/boot 190Default boot image. 191.It Pa /etc/disktab 192Disk description file. 193.El 194.Sh SAVED FILE FORMAT 195The 196.Nm 197utility 198uses an 199.Tn ASCII 200version of the label when examining, editing, or restoring a disk 201label. 202The format is: 203.Bd -literal -offset 4n 204 2058 partitions: 206# size offset fstype [fsize bsize bps/cpg] 207 a: 81920 16 4.2BSD 2048 16384 5128 208 b: 1091994 81936 swap 209 c: 1173930 0 unused 0 0 # "raw" part, don't edit 210.Ed 211.Pp 212If the 213.Fl A 214option is specified, the format is: 215.Bd -literal -offset 4n 216# /dev/da1c: 217type: SCSI 218disk: da0s1 219label: 220flags: 221bytes/sector: 512 222sectors/track: 51 223tracks/cylinder: 19 224sectors/cylinder: 969 225cylinders: 1211 226sectors/unit: 1173930 227rpm: 3600 228interleave: 1 229trackskew: 0 230cylinderskew: 0 231headswitch: 0 # milliseconds 232track-to-track seek: 0 # milliseconds 233drivedata: 0 234 2358 partitions: 236# size offset fstype [fsize bsize bps/cpg] 237 a: 81920 16 4.2BSD 1024 8192 16 238 b: 160000 81936 swap 239 c: 1173930 0 unused 0 0 # "raw" part, don't edit 240.Ed 241.Pp 242Lines starting with a 243.Ql # 244mark are comments. 245.Pp 246The partition table can have up to 8 entries. 247It contains the following information: 248.Bl -tag -width indent 249.It Ar # 250The partition identifier is a single letter in the range 251.Ql a 252to 253.Ql h . 254By convention, partition 255.Ql c 256is reserved to describe the entire disk. 257.It Ar size 258The size of the partition in sectors, 259.Cm K 260(kilobytes - 1024), 261.Cm M 262(megabytes - 1024*1024), 263.Cm G 264(gigabytes - 1024*1024*1024), 265.Cm % 266(percentage of free space 267.Em after 268removing any fixed-size partitions other than partition 269.Ql c ) , 270or 271.Cm * 272(all remaining free space 273.Em after 274fixed-size and percentage partitions). 275For partition 276.Ql c , 277a size of 278.Cm * 279indicates the entire disk. 280Lowercase versions of suffixes 281.Cm K , M , 282and 283.Cm G 284are allowed. 285Size and suffix should be specified without any spaces between them. 286.Pp 287Example: 2097152, 1G, 1024M and 1048576K are all the same size 288(assuming 512-byte sectors). 289.It Ar offset 290The offset of the start of the partition from the beginning of the 291drive in sectors, or 292.Cm * 293to have 294.Nm 295calculate the correct offset to use (the end of the previous partition plus 296one, ignoring partition 297.Ql c ) . 298For partition 299.Ql c , 300.Cm * 301will be interpreted as an offset of 0. 302The first partition should start at offset 16, because the first 16 sectors are 303reserved for metadata. 304.It Ar fstype 305Describes the purpose of the partition. 306The above example shows all currently used partition types. 307For 308.Tn UFS 309file systems and 310.Xr ccd 4 311partitions, use type 312.Cm 4.2BSD . 313For Vinum drives, use type 314.Cm vinum . 315Other common types are 316.Cm swap 317and 318.Cm unused . 319By convention, partition 320.Ql c 321represents the entire slice and should be of type 322.Cm unused , 323though 324.Nm 325does not enforce this convention. 326The 327.Nm 328utility 329also knows about a number of other partition types, 330none of which are in current use. 331(See the definitions starting with 332.Dv FS_UNUSED 333in 334.In sys/disklabel.h 335for more details.) 336.It Ar fsize 337For 338.Cm 4.2BSD 339file systems only, the fragment size; see 340.Xr newfs 8 . 341.It Ar bsize 342For 343.Cm 4.2BSD 344file systems only, the block size; see 345.Xr newfs 8 . 346.It Ar bps/cpg 347For 348.Cm 4.2BSD 349file systems, the number of cylinders in a cylinder group; see 350.Xr newfs 8 . 351.El 352.Sh EXAMPLES 353Display the label for the first slice of the 354.Pa da0 355disk, as obtained via 356.Pa /dev/da0s1 : 357.Pp 358.Dl "bsdlabel da0s1" 359.Pp 360Save the in-core label for 361.Pa da0s1 362into the file 363.Pa savedlabel . 364This file can be used with the 365.Fl R 366option to restore the label at a later date: 367.Pp 368.Dl "bsdlabel da0s1 > savedlabel" 369.Pp 370Create a label for 371.Pa da0s1 : 372.Pp 373.Dl "bsdlabel -w /dev/da0s1" 374.Pp 375Read the label for 376.Pa da0s1 , 377edit it, and install the result: 378.Pp 379.Dl "bsdlabel -e da0s1" 380.Pp 381Read the on-disk label for 382.Pa da0s1 , 383edit it, and display what the new label would be (in sectors). 384It does 385.Em not 386install the new label either in-core or on-disk: 387.Pp 388.Dl "bsdlabel -e -n da0s1" 389.Pp 390Write a default label on 391.Pa da0s1 . 392Use another 393.Nm Fl e 394command to edit the 395partitioning and file system information: 396.Pp 397.Dl "bsdlabel -w da0s1" 398.Pp 399Restore the on-disk and in-core label for 400.Pa da0s1 401from information in 402.Pa savedlabel : 403.Pp 404.Dl "bsdlabel -R da0s1 savedlabel" 405.Pp 406Display what the label would be for 407.Pa da0s1 408using the partition layout in 409.Pa label_layout . 410This is useful for determining how much space would be allotted for various 411partitions with a labeling scheme using 412.Cm % Ns -based 413or 414.Cm * 415partition sizes: 416.Pp 417.Dl "bsdlabel -R -n da0s1 label_layout" 418.Pp 419Install a new bootstrap on 420.Pa da0s1 . 421The boot code comes from 422.Pa /boot/boot : 423.Pp 424.Dl "bsdlabel -B da0s1" 425.Pp 426Install a new label and bootstrap. 427The bootstrap code comes from the file 428.Pa newboot 429in the current working directory: 430.Pp 431.Dl "bsdlabel -w -B -b newboot /dev/da0s1" 432.Pp 433Completely wipe any prior information on the disk, creating a new bootable 434disk with a 435.Tn DOS 436partition table containing one slice, covering the whole disk. 437Initialize the label on this slice, 438then edit it. 439The 440.Xr dd 1 441commands are optional, but may be necessary for some 442.Tn BIOS Ns es 443to properly 444recognize the disk: 445.Bd -literal -offset indent 446dd if=/dev/zero of=/dev/da0 bs=512 count=32 447fdisk -BI da0 448dd if=/dev/zero of=/dev/da0s1 bs=512 count=32 449bsdlabel -w -B da0s1 450bsdlabel -e da0s1 451.Ed 452.Pp 453This is an example disk label that uses some of the new partition size types 454such as 455.Cm % , M , G , 456and 457.Cm * , 458which could be used as a source file for 459.Dq Li "bsdlabel -R ad0s1 new_label_file" : 460.Bd -literal -offset 4n 461# /dev/ad0s1: 462 4638 partitions: 464# size offset fstype [fsize bsize bps/cpg] 465 a: 400M 16 4.2BSD 4096 16384 75 # (Cyl. 0 - 812*) 466 b: 1G * swap 467 c: * * unused 468 e: 204800 * 4.2BSD 469 f: 5g * 4.2BSD 470 g: * * 4.2BSD 471.Ed 472.Sh DIAGNOSTICS 473The kernel device drivers will not allow the size of a disk partition 474to be decreased or the offset of a partition to be changed while it is open. 475.Sh COMPATIBILITY 476Due to the use of an 477.Vt u_int32_t 478to store the number of sectors, 479.Bx 480labels are restricted to a maximum of 2^32-1 sectors. 481This usually means 2TB of disk space. 482Larger disks should be partitioned using another method such as 483.Xr gpt 8 . 484.Pp 485The various 486.Bx Ns s 487all use slightly different versions of 488.Bx 489labels and 490are not generally compatible. 491.Sh SEE ALSO 492.Xr ccd 4 , 493.Xr geom 4 , 494.Xr md 4 , 495.\" Xr bsdlabel 5 , 496.Xr disktab 5 , 497.Xr boot0cfg 8 , 498.Xr fdisk 8 , 499.Xr gpt 8 , 500.Xr newfs 8 501