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. 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.5.5 8.1 (Berkeley) 6/5/93 32.\" $FreeBSD: src/sbin/disklabel/disklabel.5,v 1.7.2.4 2002/08/21 18:58:16 trhodes Exp $ 33.\" $DragonFly: src/sbin/disklabel64/disklabel64.5,v 1.3 2008/08/21 21:59:23 thomas Exp $ 34.\" 35.Dd August 21, 2008 36.Dt DISKLABEL64 5 37.Os 38.Sh NAME 39.Nm disklabel64 40.Nd 64 bit disk pack label 41.Sh SYNOPSIS 42.In sys/disklabel64.h 43.Sh DESCRIPTION 44Each disk or disk pack on a system may contain a 64 bit disk label 45which provides detailed information 46the disk and the partitions into which the disk 47is divided. 48It should be initialized when the disk is formatted, 49and may be changed later with the 50.Xr disklabel64 8 51program. 52This information is used by the system disk driver 53to determine how to program the drive. 54Additional information is used by the file system in order 55to locate important file system information. 56The description of each partition contains an identifier for the partition 57type (standard file system, swap area, etc.). 58The file system updates the in-core copy of the label if it contains 59incomplete information about the file system. 60.Pp 61The label is located in byte number 0 where it may be found 62without any information about the disk geometry. 63The disk sector containing the label is normally made read-only 64so that it is not accidentally overwritten by pack-to-pack copies 65or swap operations; 66the 67.Dv DIOCWLABEL 68.Xr ioctl 2 , 69which is done as needed by the 70.Xr disklabel64 8 71program. 72.Pp 73A copy of the in-core label for a disk can be obtained with the 74.Dv DIOCGDINFO64 75.Xr ioctl 2 ; 76this works with a file descriptor for a block or character 77.Pq Dq raw 78device 79for any partition of the disk. 80The in-core copy of the label is set by the 81.Dv DIOCSDINFO64 82.Xr ioctl 2 . 83The offset of a partition cannot generally be changed while it is open, 84nor can it be made smaller while it is open. 85One exception is that any change is allowed if no label was found 86on the disk, and the driver was able to construct only a skeletal label 87without partition information. 88Finally, the 89.Dv DIOCWDINFO64 90.Xr ioctl 2 91operation sets the in-core label and then updates the on-disk label; 92there must be an existing label on the disk for this operation to succeed. 93Thus, the initial label for a disk or disk pack must be installed 94by writing to the raw disk. 95All of these operations are normally done using 96.Xr disklabel64 8 . 97.Pp 98The format of the 64 bit disk label is specified in 99.In sys/disklabel64.h . 100.Sh SEE ALSO 101.Xr disklabel32 5 , 102.Xr disktab 5 , 103.Xr disklabel64 8 104