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SUNLABEL(8)               BSD System Manager's Manual              SUNLABEL(8)

NAME
     sunlabel -- read and write disk pack label suitable for Sun's OpenBoot
     PROM

SYNOPSIS
     sunlabel [-r] [-c | -h] disk
     sunlabel -B [-b boot1] [-n] disk
     sunlabel -R [-B [-b boot1]] [-r] [-n] [-c] disk protofile
     sunlabel -e [-B [-b boot1]] [-r] [-n] [-c] disk
     sunlabel -w [-B [-b boot1]] [-r] [-n] [-c] disk type

DESCRIPTION
     The sunlabel utility installs, examines or modifies the Sun OpenBoot PROM
     label on a disk.  In addition, sunlabel can install bootstrap code.

   Introduction
     The label occupies the first sector (i.e., 512 bytes) of each disk.  It
     starts with a textual description which by convention also mentions the
     disk geometry in textual form (number of cylinders, alternate cylinders,
     heads, and sectors per track), optionally followed by a table of
     SVR4-compatible VTOC tags and flags per partition, followed by the parti-
     tion table itself.  Finally, a checksum is recorded to ensure the label
     has not been tampered with.

     The Sun OpenBoot PROM label allows for 8 disk partitions.  The partition
     table lists the starting cylinder of the partition, plus the size of the
     partition in 512-byte sectors.  Thus, partitions in the Sun OpenBoot PROM
     must always start at a cylinder boundary (for whatever geometry emulation
     has been chosen).

     The optional SVR4-compatible VTOC tag and flags table is not used by the
     FreeBSD kernel.  It is maintained solely for compatibilty with the
     Solaris operating system that might share disks with FreeBSD on the same
     hardware platform.

     The Sun OpenBoot PROM label is natively understood by the underlying
     hardware, which can bootstrap from a single partition entry, as opposed
     to the very first block(s) of the entire disk as on many other hardware
     platforms.

     Note that the hardware platform mandates that two cylinders are set aside
     as alternate cylinders which are not available to user programs (and not
     even through the ``backup'' partition).

   Options
     Options are listed in alphabetical order here.  Note that only those
     option combinations listed under SYNOPSIS are allowable.

     -b bootpath  Specify that bootpath is to be used as the boot image,
                  rather than the default of /boot/boot1.

     -B           Install bootstrap code onto the disk.  Note that since the
                  underlying hardware platform bootstraps from partitions, not
                  disks, this operation is only useful if there is a partition
                  starting at offset 0.

     -c           Use cylinders for partition size display rather than
                  (512-byte) sectors.  This also changes the default interpre-
                  tation of the partition size entries when editing the label,
                  or reading from a prototype file.  Thus, prototype files are
                  only compatible when both, obtaining the file and re-
                  installing it is done using the same -c option setting.

     -e           Enter edit mode.  See Edit mode below for a more detailed
                  explanation.

     -h           When displaying the label, make the partition size and off-
                  set values ``human readable''.  The displayed numbers will
                  get a suffix of 'B' for bytes, 'K' for 1024 bytes each, 'M'
                  for 1048576 bytes each, or 'G' for 1073741824 bytes each
                  appended.  Note that due to possible rounding errors, proto-
                  type files obtained using the -h option are not suited for
                  re-installing using the -R option.

     -n           No changes.  All operations, checks etc., are performed nor-
                  mally, but nothing is written to disk.

     -r           Obsolete option that used to indicate that the operation
                  should be done directly on disk, as opposed through the
                  respective kernel services.  Ignored.

     -R           Restore label from the prototype in protofile.  A prototype
                  file is simply the textual representation of the label as
                  printed using the first form of the sunlabel utility shown
                  in the SYNOPSIS.  Note that the -c option used to obtain the
                  prototype must match the option used when restoring the
                  label (both present, or both absent).

     -w           Write mode.  Suitable to write an initial label to disk.
                  The type argument used to be an entry into a table of prede-
                  fined labels, but this functionality is not supported by
                  sunlabel.  Instead, the only allowable type argument is the
                  string ``auto'', indicating that an automatically created
                  label should be written to disk.  This automatism will try
                  to create an initial label that fits as best as possible
                  into the available disk capacity.

     If neither of the -e, -R, or -w options are present, the existing label
     for disk will be printed to standard output.

     The disk argument must be given as a plain disk name, without any leading
     /dev/.

   Edit mode
     In edit mode, the existing label from disk will be read, and put into a
     template file.  The command referenced by the EDITOR environmental vari-
     able will be started to allow the user to edit the label.  The label is
     then checked and examined for any errors.  If no errors have been found,
     the new label is written to disk.  If there were any errors, a message is
     printed to standard error output, and the user is given the opportunity
     to edit the template file again.  If accepted, editing starts over.  If
     declined, no changes will be written to disk.

     The label presented for editing is the same as the standard printout,
     with some added hints about the possible options to specify the sector
     size and starting cylinder.  There are two areas in the template that can
     be edited:

     Textual label, geometry emulation
             The line
                   text: XXXX cyl CC alt 2 hd HH sec SS
             represents the label text.  It must be retained exactly in the
             form shown.  The editable text XXXX is a simple (non-whitespace)
             text describing the disk.  By convention, this text mentions the
             approximate size of the disk, as in ``SUN9.0G'' for a 9 GB disk
             shipped by Sun.

             The values CC, HH, and SS describe the number of cylinders, heads
             (tracks per cylinder), and sectors per track respectively.  They
             might be modified to change the geometry emulation.  Each number
             must be between 1 and 65535.  The product
                   (CC + 2) * HH * SS
             must be less than or equal to the total number of sectors of the
             disk (which is given as a hint in a comment field).

     Partition entries
             Partition entries start with a letter from 'a' through 'h', imme-
             diately followed by a colon, followed by the size of this parti-
             tion, and the starting cylinder of the partition.  The unit of
             the size field defaults to sectors, or to cylinders if the -c
             option is in effect.  Alternatively, a different unit may be
             specified by appending 's' for (512-byte) sectors, 'c' for cylin-
             ders, 'k' for kilobytes, 'm' for megabytes, or 'g' for gigabytes.
             The last partition entry may specify the size as '*' to indicate
             that this entry should consume the rest of disk not consumed by
             any other partition so far.

             The start of partition is always taken as a cylinder number
             (starting at 0) since this is what the underlying hardware uses.
             Alternatively, specifying it as '*' will make the computation
             automatically chose the nearest possible cylinder boundary.

             Partition 'c' must always be present, must start at 0, and must
             cover the entire disk (without considering the alternate cylin-
             ders though).

             Optionally, each partition entry may be followed by an SVR4-com-
             patible VTOC tag name, and a flag description.  The following
             VTOC tag names are known:

                   name          value    comment
                   unassigned    0x00
                   boot          0x01
                   root          0x02
                   swap          0x03
                   usr           0x04
                   backup        0x05     c partition, entire disk
                   stand         0x06
                   var           0x07
                   home          0x08
                   altsctr       0x09     alternate sector partition
                   cache         0x0a     Solaris cachefs partition
                   VxVM_pub      0x0e     VxVM public region
                   VxVM_priv     0x0f     VxVM private region

             The following VTOC flags are known:

                   name    value    comment
                   wm      0x00     read/write, mountable
                   wu      0x01     read/write, unmountable
                   rm      0x10     read/only, mountable
                   ru      0x11     read/only, unmountable

             Optionally, both the tag and/or the flag name may be specified
             numerically, using standard 'C' numerial notation (prefix '0x'
             for hexadecimal numbers, '0' for octal numbers).  If the flag
             field is omitted, it defaults to 'wm'.  If the tag field is also
             omitted, it defaults to ``unassigned''.  If none of the parti-
             tions lists any VTOC tag/flags, no SVR4-compatible VTOC elements
             will be written to disk.  If VTOC-style elements are present,
             partition 'c' must be marked as ``backup'' (and should be marked
             'wu').

     When checking the label, partition 'c' is checked for presence, and for
     the mentioned restrictions.  All other partitions are checked for possi-
     ble overlaps, as well as for not extending past the end of unit.  If
     VTOC-style elements are present, overlaps of unmountable partitions
     against other partitions will be warned still but do not cause a rejec-
     tion of the label.  That way, encapsulated disks of volume management
     software are acceptable as long as the volume management partitions are
     clearly marked as unmountable.

     Any other fields in the label template are informational only, and will
     not be parsed when reading the label.

     Note that when changing the geometry emulation by editing the textual
     description line, all partition entries will be considered based on the
     new geometry emulation.

ENVIRONMENT
     EDITOR  Name of the command to edit the template file in edit-mode.
             Defaults to vi(1).

FILES
     /boot/boot1  Default boot image.

SEE ALSO
     vi(1), geom(4), bsdlabel(8)

HISTORY
     The sunlabel utility appeared in FreeBSD 5.1.

AUTHORS
     The sunlabel utility was written by Jake Burkholder, modeling it after
     the bsdlabel(8) command available on other architectures.

     This man page was initially written by David O'Brien, and later substan-
     tially updated by Jrg Wunsch.

BUGS
     Installing bootstrap code onto an entire disk is merely pointless.
     sunlabel should rather support installing bootstrap code into a partition
     instead.

     The ``auto'' layout algorithm could be smarter.  By now, it tends to emu-
     late fairly large cylinders which due to the two reserved alternate
     cylinders causes a fair amount of wasted disk space.

BSD                              June 1, 2004                              BSD