.\" $NetBSD: disklabel.8,v 1.18 1997/10/11 02:28:17 enami Exp $ .\" .\" Copyright (c) 1987, 1988, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" Symmetric Computer Systems. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)disklabel.8 8.2 (Berkeley) 4/19/94 .\" .Dd April 19, 1994 .Dt DISKLABEL 8 .Os BSD 4.2 .Sh NAME .Nm disklabel .Nd read and write disk pack label .Sh SYNOPSIS .Nm .Op Fl rt .Ar disk .Nm "" .Fl w .Op Fl r .Ar disk Ar disktype .Oo Ar packid Oc .Nm "" .Fl e .Op Fl r .Ar disk .Nm "" .Fl i .Op Fl r .Ar disk .Nm "" .Fl R .Op Fl r .Ar disk Ar protofile .Nm "" .Op Fl NW .Ar disk .sp .Nm "" .Fl B .Oo .Fl b Ar boot1 .Op Fl s Ar boot2 .Oc .Ar disk .Oo Ar disktype Oc .Nm "" .Fl w .Fl B .Oo .Fl b Ar boot1 .Op Fl s Ar boot2 .Oc .Ar disk Ar disktype .Oo Ar packid Oc .Nm "" .Fl R .Fl B .Oo .Fl b Ar boot1 .Op Fl s Ar boot2 .Oc .Ar disk Ar protofile .Oo Ar disktype Oc .Sh DESCRIPTION .Nm can be used to install, examine or modify the label on a disk drive or pack. When writing the label, it can be used to change the drive identification, the disk partitions on the drive, or to replace a damaged label. On some systems, .Nm can be used to install bootstrap code as well. There are several forms of the command that read (display), install or edit the label on a disk. Each form has an additional option, .Fl r , which causes the label to be read from or written to the disk directly, rather than going through the system's in-core copy of the label. This option may allow a label to be installed on a disk without kernel support for a label, such as when labels are first installed on a system; it must be used when first installing a label on a disk. The specific effect of .Fl r is described under each command. The read and install forms also support the .Fl B option to install bootstrap code. These variants are described later. .Pp The first form of the command (read) is used to examine the label on the named disk drive (e.g. sd0 or /dev/rsd0c). It will display all of the parameters associated with the drive and its partition layout. Unless the .Fl r flag is given, the kernel's in-core copy of the label is displayed; if the disk has no label, or the partition types on the disk are incorrect, the kernel may have constructed or modified the label. If the .Fl r flag is given, the label from the raw disk will be displayed rather than the in-core label. If the .Fl t flag is given, then the label will be formatted as a .Xr disktab 5 entry. .Pp The second form of the command, with the .Fl w flag, is used to write a standard label on the designated drive. The required arguments to .Nm are the drive to be labelled (e.g. sd0), and the drive type as described in the .Xr disktab 5 file. The drive parameters and partitions are taken from that file. If different disks of the same physical type are to have different partitions, it will be necessary to have separate disktab entries describing each, or to edit the label after installation as described below. The optional argument is a pack identification string, up to 16 characters long. The pack id must be quoted if it contains blanks. If the .Fl r flag is given, the disk sectors containing the label and bootstrap will be written directly. A side-effect of this is that any existing bootstrap code will be overwritten and the disk rendered unbootable. If .Fl r is not specified, the existing label will be updated via the in-core copy and any bootstrap code will be unaffected. If the disk does not already have a label, the .Fl r flag must be used. In either case, the kernel's in-core label is replaced. .Pp An existing disk label may be edited by using the .Fl e flag. The label is read from the in-core kernel copy, or directly from the disk if the .Fl r flag is also given. The label is formatted and then supplied to an editor for changes. If no editor is specified in an .Ev EDITOR environment variable, .Xr vi 1 is used. When the editor terminates, the formatted label is reread and used to rewrite the disk label. Existing bootstrap code is unchanged regardless of whether .Fl r was specified. .Pp Labels can also created interactively using the .Fl e flag. The .Fl C flag causes the partition offset and size values to be displayed in .Aq cylinder/track/sector format. Note that, regardless of whether .Fl C was specified, this format is always accepted by .Nm on input with either the .Fl e No or Fl R No flag. .Pp With the .Fl R flag, .Nm is capable of restoring a disk label that was formatted in a prior operation and saved in an ascii file. The prototype file used to create the label should be in the same format as that produced when reading or editing a label. Comments are delimited by .Ar \&# and newline. As with .Fl w , any existing bootstrap code will be clobbered if .Fl r is specified and will be unaffected otherwise. .Pp The .Fl NW flags for .Nm explicitly disallow and allow, respectively, writing of the pack label area on the selected disk. .Pp The final three forms of .Nm are used to install boostrap code on machines where the bootstrap is part of the label. The bootstrap code is comprised of one or two boot programs depending on the machine. The .Fl B option is used to denote that bootstrap code is to be installed. The .Fl r flag is implied by .Fl B and never needs to be specified. The name of the boot program(s) to be installed can be selected in a variety of ways. First, the names can be specified explicitly via the .Fl b and .Fl s flags. On machines with only a single level of boot program, .Fl b is the name of that program. For machines with a two-level bootstrap, .Fl b indicates the primary boot program and .Fl s the secondary boot program. If the names are not explicitly given, standard boot programs will be used. The boot programs are located in .Pa /usr/mdec . The names of the programs are taken from the ``b0'' and ``b1'' parameters of the .Xr disktab 5 entry for the disk if .Ar disktype was given and its disktab entry exists and includes those parameters. Otherwise, boot program names are derived from the name of the disk. These names are of the form .Pa basename Ns boot for the primary (or only) bootstrap, and .Pf boot Pa basename for the secondary bootstrap; for example, .Pa /usr/mdec/sdboot and .Pa /usr/mdec/bootsd if the disk device is .Em sd0 . .Pp The first of the three boot-installation forms is used to install bootstrap code without changing the existing label. It is essentially a read command with respect to the disk label itself and all options are related to the specification of the boot program as described previously. The final two forms are analogous to the basic write and restore versions except that they will install bootstrap code in addition to a new label. .Sh FILES .Bl -tag -width Pa -compact .It Pa /etc/disktab .It Pa /usr/mdec/ Ns Em xx Ns boot .It Pa /usr/mdec/boot Ns Em xx .El .Sh EXAMPLES .Dl disklabel sd0 .Pp Display the in-core label for sd0 as obtained via .Pa /dev/rsd0c . .Pp .Dl disklabel -w -r /dev/rsd0c sd2212 foo .Pp Create a label for sd0 based on information for ``sd2212'' found in .Pa /etc/disktab , using .Pa foo as the disk pack label. Any existing bootstrap code will be clobbered. If you do not have an entry for your disk in .Pa /etc/disktab , you can use this style to put an initial label onto a new disk. Then dump the label to a file (using .Em disklabel sd0 > .Em protofile ) , editing the file, and replacing the label with .Em disklabel -R sd0 .Em protofile . .Pp .Dl disklabel -e -r sd0 .Pp Read the on-disk label for sd0, edit it and reinstall in-core as well as on-disk. Existing bootstrap code is unaffected. .Pp .Dl disklabel -R sd0 mylabel .Pp Restore the on-disk and in-core label for sd0 from information in .Pa mylabel . Existing bootstrap code is unaffected. .Pp .Dl disklabel -B sd0 .Pp Install a new bootstrap on sd0. The boot code comes from .Pa /usr/mdec/sdboot and possibly .Pa /usr/mdec/bootsd . On-disk and in-core labels are unchanged. .Pp .Dl disklabel -w -B /dev/rsd0c -b newboot sd2212 .Pp Install a new label and bootstrap. The label is derived from disktab information for ``sd2212'' and installed both in-core and on-disk. The bootstrap code comes from the file .Pa /usr/mdec/newboot . .Pp .Dl disklabel -R -r sd0 .Pp Install a new label and bootstrap on a disk, from a prototype label file. This is a good way to install a label on a previously unlabeled disk for which no entry appears in .Pa /etc/disktab , if you create the prototype file by dumping some other disk's label to a file and editing it appropriately (total size, partition offsets, types, etc.) .Sh SEE ALSO .Xr disktab 5 , .Xr disklabel 5 , .Xr installboot 8 .Sh DIAGNOSTICS The kernel device drivers will not allow the size of a disk partition to be decreased or the offset of a partition to be changed while it is open. Some device drivers create a label containing only a single large partition if a disk is unlabeled; thus, the label must be written to the ``a'' partition of the disk while it is open. This sometimes requires the desired label to be set in two steps, the first one creating at least one other partition, and the second setting the label on the new partition while shrinking the ``a'' partition. .Pp On some machines the bootstrap code may not fit entirely in the area allocated for it by some filesystems. As a result, it may not be possible to have filesystems on some partitions of a ``bootable'' disk. When installing bootstrap code, .Nm checks for these cases. If the installed boot code would overlap a partition of type FS_UNUSED it is marked as type FS_BOOT. The .Xr newfs 8 utility will disallow creation of filesystems on FS_BOOT partitions. Conversely, if a partition has a type other than FS_UNUSED or FS_BOOT, .Nm will not install bootstrap code that overlaps it. .Sh BUGS If the disk partition is not specified in the disk name (i.e. ``xy0'' instead of ``/dev/rxy0c''), .Nm will construct the full pathname of the disk and use the ``a'' partition on the tahoe, the ``d'' partition on the i386 or its successors, and the ``c'' partition on all others.