1.\" $NetBSD: disklabel.5,v 1.21 2002/10/02 11:05:56 wiz Exp $ 2.\" 3.\" Copyright (c) 1987, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" Symmetric Computer Systems. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the University of 20.\" California, Berkeley and its contributors. 21.\" 4. Neither the name of the University nor the names of its contributors 22.\" may be used to endorse or promote products derived from this software 23.\" without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35.\" SUCH DAMAGE. 36.\" 37.\" @(#)disklabel.5.5 8.1 (Berkeley) 6/5/93 38.\" 39.Dd June 5, 1993 40.Dt DISKLABEL 5 41.Os 42.Sh NAME 43.Nm disklabel 44.Nd disk pack label 45.Sh SYNOPSIS 46.Fd #include \*[Lt]sys/disklabel.h\*[Gt] 47.Sh DESCRIPTION 48Each disk or disk pack on a system may contain a disk label 49which provides detailed information 50about the geometry of the disk and the partitions into which the disk 51is divided. 52It should be initialized when the disk is formatted, 53and may be changed later with the 54.Xr disklabel 8 55program. 56This information is used by the system disk driver and by the bootstrap 57program to determine how to program the drive 58and where to find the file systems on the disk partitions. 59Additional information is used by the file system in order 60to use the disk most efficiently and to locate important file system information. 61The description of each partition contains an identifier for the partition 62type (standard file system, swap area, etc.). 63The file system updates the in-core copy of the label if it contains 64incomplete information about the file system. 65.Pp 66The label is located in sector number 67.Dv LABELSECTOR 68of the drive, usually sector 0 where it may be found 69without any information about the disk geometry. 70It is at an offset 71.Dv LABELOFFSET 72from the beginning of the sector, to allow room for the initial bootstrap. 73The disk sector containing the label is normally made read-only 74so that it is not accidentally overwritten by pack-to-pack copies 75or swap operations; 76the 77.Dv DIOCWLABEL 78.Xr ioctl 2 , 79which is done as needed by the 80.Xr disklabel 8 81program. 82.Pp 83A copy of the in-core label for a disk can be obtained with the 84.Dv DIOCGDINFO 85.Xr ioctl 2 ; 86this works with a file descriptor for a block or character (``raw'') device 87for any partition of the disk. 88The in-core copy of the label is set by the 89.Dv DIOCSDINFO 90.Xr ioctl 2 . 91The offset of a partition cannot generally be changed while it is open, 92nor can it be made smaller while it is open. 93One exception is that any change is allowed if no label was found 94on the disk, and the driver was able to construct only a skeletal label 95without partition information. 96Finally, the 97.Dv DIOCWDINFO 98.Xr ioctl 2 99operation sets the in-core label and then updates the on-disk label; 100there must be an existing label on the disk for this operation to succeed. 101Thus, the initial label for a disk or disk pack must be installed 102by writing to the raw disk. 103All of these operations are normally done using 104.Xr disklabel 8 . 105.Pp 106The format of the disk label, as specified in 107.Pa sys/disklabel.h , 108is 109.Bd -literal 110/* 111 * Disk description table, see disktab(5) 112 */ 113#define _PATH_DISKTAB "/etc/disktab" 114 115/* 116 * Each disk has a label which includes information about the hardware 117 * disk geometry, file system partitions, and drive specific information. 118 * The location of the label, as well as the number of partitions the 119 * label can describe and the number of the "whole disk" (raw) 120 * partition are machine dependent. 121 */ 122#include \*[Lt]machine/disklabel.h\*[Gt] 123 124/* 125 * The absolute maximum number of disk partitions allowed. 126 * This is the maximum value of MAXPARTITIONS for which 'struct disklabel' 127 * is \*[Le] DEV_BSIZE bytes long. If MAXPARTITIONS is greater than this, beware. 128 */ 129#define MAXMAXPARTITIONS 22 130#if MAXPARTITIONS \*[Gt] MAXMAXPARTITIONS 131#warning beware: MAXPARTITIONS bigger than MAXMAXPARTITIONS 132#endif 133 134 135#define DISKMAGIC ((u_int32_t)0x82564557) /* The disk magic number */ 136 137#ifndef _LOCORE 138struct disklabel { 139 u_int32_t d_magic; /* the magic number */ 140 u_int16_t d_type; /* drive type */ 141 u_int16_t d_subtype; /* controller/d_type specific */ 142 char d_typename[16]; /* type name, e.g. "eagle" */ 143 144 /* 145 * d_packname contains the pack identifier and is returned when 146 * the disklabel is read off the disk or in-core copy. 147 * d_boot0 and d_boot1 are the (optional) names of the 148 * primary (block 0) and secondary (block 1-15) bootstraps 149 * as found in /usr/mdec. These are returned when using 150 * getdiskbyname(3) to retrieve the values from /etc/disktab. 151 */ 152 union { 153 char un_d_packname[16]; /* pack identifier */ 154 struct { 155 char *un_d_boot0; /* primary bootstrap name */ 156 char *un_d_boot1; /* secondary bootstrap name */ 157 } un_b; 158 } d_un; 159#define d_packname d_un.un_d_packname 160#define d_boot0 d_un.un_b.un_d_boot0 161#define d_boot1 d_un.un_b.un_d_boot1 162 163 /* disk geometry: */ 164 u_int32_t d_secsize; /* # of bytes per sector */ 165 u_int32_t d_nsectors; /* # of data sectors per track */ 166 u_int32_t d_ntracks; /* # of tracks per cylinder */ 167 u_int32_t d_ncylinders; /* # of data cylinders per unit */ 168 u_int32_t d_secpercyl; /* # of data sectors per cylinder */ 169 u_int32_t d_secperunit; /* # of data sectors per unit */ 170 171 /* 172 * Spares (bad sector replacements) below are not counted in 173 * d_nsectors or d_secpercyl. Spare sectors are assumed to 174 * be physical sectors which occupy space at the end of each 175 * track and/or cylinder. 176 */ 177 u_int16_t d_sparespertrack; /* # of spare sectors per track */ 178 u_int16_t d_sparespercyl; /* # of spare sectors per cylinder */ 179 /* 180 * Alternative cylinders include maintenance, replacement, 181 * configuration description areas, etc. 182 */ 183 u_int32_t d_acylinders; /* # of alt. cylinders per unit */ 184 185 /* hardware characteristics: */ 186 /* 187 * d_interleave, d_trackskew and d_cylskew describe perturbations 188 * in the media format used to compensate for a slow controller. 189 * Interleave is physical sector interleave, set up by the 190 * formatter or controller when formatting. When interleaving is 191 * in use, logically adjacent sectors are not physically 192 * contiguous, but instead are separated by some number of 193 * sectors. It is specified as the ratio of physical sectors 194 * traversed per logical sector. Thus an interleave of 1:1 195 * implies contiguous layout, while 2:1 implies that logical 196 * sector 0 is separated by one sector from logical sector 1. 197 * d_trackskew is the offset of sector 0 on track N relative to 198 * sector 0 on track N-1 on the same cylinder. Finally, d_cylskew 199 * is the offset of sector 0 on cylinder N relative to sector 0 200 * on cylinder N-1. 201 */ 202 u_int16_t d_rpm; /* rotational speed */ 203 u_int16_t d_interleave; /* hardware sector interleave */ 204 u_int16_t d_trackskew; /* sector 0 skew, per track */ 205 u_int16_t d_cylskew; /* sector 0 skew, per cylinder */ 206 u_int32_t d_headswitch; /* head switch time, usec */ 207 u_int32_t d_trkseek; /* track-to-track seek, usec */ 208 u_int32_t d_flags; /* generic flags */ 209#define NDDATA 5 210 u_int32_t d_drivedata[NDDATA]; /* drive-type specific information */ 211#define NSPARE 5 212 u_int32_t d_spare[NSPARE]; /* reserved for future use */ 213 u_int32_t d_magic2; /* the magic number (again) */ 214 u_int16_t d_checksum; /* xor of data incl. partitions */ 215 216 /* file system and partition information: */ 217 u_int16_t d_npartitions; /* number of partitions in following */ 218 u_int32_t d_bbsize; /* size of boot area at sn0, bytes */ 219 u_int32_t d_sbsize; /* max size of fs superblock, bytes */ 220 struct partition { /* the partition table */ 221 u_int32_t p_size; /* number of sectors in partition */ 222 u_int32_t p_offset; /* starting sector */ 223 u_int32_t p_fsize; /* file system basic fragment size */ 224 u_int8_t p_fstype; /* file system type, see below */ 225 u_int8_t p_frag; /* file system fragments per block */ 226 union { 227 u_int16_t cpg; /* UFS: FS cylinders per group */ 228 u_int16_t sgs; /* LFS: FS segment shift */ 229 } __partition_u1; 230#define p_cpg __partition_u1.cpg 231#define p_sgs __partition_u1.sgs 232 } d_partitions[MAXPARTITIONS]; /* actually may be more */ 233}; 234#else /* _LOCORE */ 235 /* 236 * offsets for asm boot files. 237 */ 238 .set d_secsize,40 239 .set d_nsectors,44 240 .set d_ntracks,48 241 .set d_ncylinders,52 242 .set d_secpercyl,56 243 .set d_secperunit,60 244 .set d_end_,276 /* size of disk label */ 245#endif /* _LOCORE */ 246 247/* d_type values: */ 248#define DTYPE_SMD 1 /* SMD, XSMD; VAX hp/up */ 249#define DTYPE_MSCP 2 /* MSCP */ 250#define DTYPE_DEC 3 /* other DEC (rk, rl) */ 251#define DTYPE_SCSI 4 /* SCSI */ 252#define DTYPE_ESDI 5 /* ESDI interface */ 253#define DTYPE_ST506 6 /* ST506 etc. */ 254#define DTYPE_HPIB 7 /* CS/80 on HP-IB */ 255#define DTYPE_HPFL 8 /* HP Fiber-link */ 256#define DTYPE_FLOPPY 10 /* floppy */ 257#define DTYPE_CCD 11 /* concatenated disk device */ 258#define DTYPE_VND 12 /* vnode pseudo-disk */ 259#define DTYPE_ATAPI 13 /* ATAPI */ 260#define DTYPE_RAID 14 /* RAIDframe */ 261#define DTYPE_LD 15 /* logical disk */ 262#define DTYPE_JFS2 16 /* IBM JFS2 */ 263 264#ifdef DKTYPENAMES 265static const char *const dktypenames[] = { 266 "unknown", 267 "SMD", 268 "MSCP", 269 "old DEC", 270 "SCSI", 271 "ESDI", 272 "ST506", 273 "HP-IB", 274 "HP-FL", 275 "type 9", 276 "floppy", 277 "ccd", 278 "vnd", 279 "ATAPI", 280 "RAID", 281 "ld", 282 "jfs", 283 NULL 284}; 285#define DKMAXTYPES (sizeof(dktypenames) / sizeof(dktypenames[0]) - 1) 286#endif 287 288/* 289 * Filesystem type and version. 290 * Used to interpret other file system-specific 291 * per-partition information. 292 */ 293#define FS_UNUSED 0 /* unused */ 294#define FS_SWAP 1 /* swap */ 295#define FS_V6 2 /* Sixth Edition */ 296#define FS_V7 3 /* Seventh Edition */ 297#define FS_SYSV 4 /* System V */ 298#define FS_V71K 5 /* V7 with 1K blocks (4.1, 2.9) */ 299#define FS_V8 6 /* Eighth Edition, 4K blocks */ 300#define FS_BSDFFS 7 /* 4.2BSD fast file system */ 301#define FS_MSDOS 8 /* MSDOS file system */ 302#define FS_BSDLFS 9 /* 4.4BSD log-structured file system */ 303#define FS_OTHER 10 /* in use, but unknown/unsupported */ 304#define FS_HPFS 11 /* OS/2 high-performance file system */ 305#define FS_ISO9660 12 /* ISO 9660, normally CD-ROM */ 306#define FS_BOOT 13 /* partition contains bootstrap */ 307#define FS_ADOS 14 /* AmigaDOS fast file system */ 308#define FS_HFS 15 /* Macintosh HFS */ 309#define FS_FILECORE 16 /* Acorn Filecore Filing System */ 310#define FS_EX2FS 17 /* Linux Extended 2 file system */ 311#define FS_NTFS 18 /* Windows/NT file system */ 312#define FS_RAID 19 /* RAIDframe component */ 313#define FS_CCD 20 /* concatenated disk component */ 314#define FS_JFS2 21 /* IBM JFS2 */ 315#define FS_APPLEUFS 22 /* Apple UFS */ 316 317#ifdef FSTYPENAMES 318static const char *const fstypenames[] = { 319 "unused", 320 "swap", 321 "Version 6", 322 "Version 7", 323 "System V", 324 "4.1BSD", 325 "Eighth Edition", 326 "4.2BSD", 327 "MSDOS", 328 "4.4LFS", 329 "unknown", 330 "HPFS", 331 "ISO9660", 332 "boot", 333 "ADOS", 334 "HFS", 335 "FILECORE", 336 "Linux Ext2", 337 "NTFS", 338 "RAID", 339 "ccd", 340 "jfs", 341 "Apple UFS", 342 NULL 343}; 344#define FSMAXTYPES (sizeof(fstypenames) / sizeof(fstypenames[0]) - 1) 345#endif 346 347/* 348 * flags shared by various drives: 349 */ 350#define D_REMOVABLE 0x01 /* removable media */ 351#define D_ECC 0x02 /* supports ECC */ 352#define D_BADSECT 0x04 /* supports bad sector forw. */ 353#define D_RAMDISK 0x08 /* disk emulator */ 354#define D_CHAIN 0x10 /* can do back-back transfers */ 355 356/* 357 * Drive data for SMD. 358 */ 359 360#define d_smdflags d_drivedata[0] 361#define D_SSE 0x1 /* supports skip sectoring */ 362#define d_mindist d_drivedata[1] 363#define d_maxdist d_drivedata[2] 364#define d_sdist d_drivedata[3] 365 366/* 367 * Drive data for ST506. 368 */ 369#define d_precompcyl d_drivedata[0] 370#define d_gap3 d_drivedata[1] /* used only when formatting */ 371 372/* 373 * Drive data for SCSI. 374 */ 375#define d_blind d_drivedata[0] 376 377#ifndef _LOCORE 378/* 379 * Structure used to perform a format or other raw operation, 380 * returning data and/or register values. Register identification 381 * and format are device- and driver-dependent. 382 */ 383struct format_op { 384 char *df_buf; 385 int df_count; /* value-result */ 386 daddr_t df_startblk; 387 int df_reg[8]; /* result */ 388}; 389 390/* 391 * Structure used internally to retrieve information about a partition 392 * on a disk. 393 */ 394struct partinfo { 395 struct disklabel *disklab; 396 struct partition *part; 397}; 398.Ed 399.Pp 400Disk specific ioctls are defined in 401.Pa sys/dkio.h . 402.Pp 403.Bd -literal 404/* 405 * Disk-specific ioctls. 406 */ 407 /* get and set disklabel; DIOCGPART used internally */ 408#define DIOCGDINFO _IOR('d', 101, struct disklabel) /* get */ 409#define DIOCSDINFO _IOW('d', 102, struct disklabel) /* set */ 410#define DIOCWDINFO _IOW('d', 103, struct disklabel) /* set, update disk */ 411#define DIOCGPART _IOW('d', 104, struct partinfo) /* get partition */ 412 413 /* do format operation, read or write */ 414#define DIOCRFORMAT _IOWR('d', 105, struct format_op) 415#define DIOCWFORMAT _IOWR('d', 106, struct format_op) 416 417#define DIOCSSTEP _IOW('d', 107, int) /* set step rate */ 418#define DIOCSRETRIES _IOW('d', 108, int) /* set # of retries */ 419#define DIOCKLABEL _IOW('d', 119, int) /* keep/drop label on close? */ 420#define DIOCWLABEL _IOW('d', 109, int) /* write en/disable label */ 421 422#define DIOCSBAD _IOW('d', 110, struct dkbad) /* set kernel dkbad */ 423#define DIOCEJECT _IOW('d', 112, int) /* eject removable disk */ 424#define DIOCLOCK _IOW('d', 113, int) /* lock/unlock pack */ 425 426 /* get default label, clear label */ 427#define DIOCGDEFLABEL _IOR('d', 114, struct disklabel) 428#define DIOCCLRLABEL _IO('d', 115) 429.Ed 430.Sh SEE ALSO 431.Xr disktab 5 , 432.Xr disklabel 8 433.\" .Sh HISTORY 434