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