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 acknowledgment: 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.\" $FreeBSD: src/sbin/disklabel/disklabel.5,v 1.7.2.4 2002/08/21 18:58:16 trhodes Exp $ 37.\" $DragonFly: src/sbin/disklabel64/disklabel64.5,v 1.3 2008/08/21 21:59:23 thomas Exp $ 38.\" 39.Dd August 21, 2008 40.Dt DISKLABEL64 5 41.Os 42.Sh NAME 43.Nm disklabel64 44.Nd 64 bit disk pack label 45.Sh SYNOPSIS 46.In sys/disklabel64.h 47.Sh DESCRIPTION 48Each disk or disk pack on a system may contain a 64 bit disk label 49which provides detailed information 50the 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 disklabel64 8 55program. 56This information is used by the system disk driver 57to determine how to program the drive. 58Additional information is used by the file system in order 59to locate important file system information. 60The description of each partition contains an identifier for the partition 61type (standard file system, swap area, etc.). 62The file system updates the in-core copy of the label if it contains 63incomplete information about the file system. 64.Pp 65The label is located in byte number 0 where it may be found 66without any information about the disk geometry. 67The disk sector containing the label is normally made read-only 68so that it is not accidentally overwritten by pack-to-pack copies 69or swap operations; 70the 71.Dv DIOCWLABEL 72.Xr ioctl 2 , 73which is done as needed by the 74.Xr disklabel64 8 75program. 76.Pp 77A copy of the in-core label for a disk can be obtained with the 78.Dv DIOCGDINFO64 79.Xr ioctl 2 ; 80this works with a file descriptor for a block or character 81.Pq Dq raw 82device 83for any partition of the disk. 84The in-core copy of the label is set by the 85.Dv DIOCSDINFO64 86.Xr ioctl 2 . 87The offset of a partition cannot generally be changed while it is open, 88nor can it be made smaller while it is open. 89One exception is that any change is allowed if no label was found 90on the disk, and the driver was able to construct only a skeletal label 91without partition information. 92Finally, the 93.Dv DIOCWDINFO64 94.Xr ioctl 2 95operation sets the in-core label and then updates the on-disk label; 96there must be an existing label on the disk for this operation to succeed. 97Thus, the initial label for a disk or disk pack must be installed 98by writing to the raw disk. 99All of these operations are normally done using 100.Xr disklabel64 8 . 101.Pp 102The format of the 64 bit disk label is specified in 103.In sys/disklabel64.h . 104.Sh SEE ALSO 105.Xr disklabel32 5 , 106.Xr disktab 5 , 107.Xr disklabel64 8 108