

DISKLABEL(8)                                         DISKLABEL(8)


NNAAMMEE
       disklabel - read and write disk pack label

SSYYNNOOPPSSIISS
       ddiisskkllaabbeell [ --rr ] _d_i_s_k
       ddiisskkllaabbeell  --ww [ --rr ] _d_i_s_k _d_i_s_k_t_y_p_e [ _p_a_c_k_i_d [ _p_r_i_b_o_o_t _s_e_c_-
       _b_o_o_t ] ]
       ddiisskkllaabbeell --ee [ --rr ] _d_i_s_k
       ddiisskkllaabbeell --RR [ --rr ] _d_i_s_k _p_r_o_t_o_f_i_l_e [ _p_r_i_b_o_o_t _s_e_c_b_o_o_t ]
       ddiisskkllaabbeell [ --NNWW ] _d_i_s_k

DDEESSCCRRIIPPTTIIOONN
       _D_i_s_k_l_a_b_e_l 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 or
       bootstrap.  The disk label is located on one of the  first
       sectors  of each disk (usually block 0).  On machines that
       require a block-0 bootstrap (VAX  11/750),  the  label  is
       inserted  into the bootstrap program.  This information is
       used by the system disk driver and by the  bootstrap  pro-
       gram  to  determine  how  to program the drive.  There are
       several forms of the command that display, install or mod-
       ify  the  label  on  a  disk.  Each form has an additional
       option, --r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.  When writing, the
       in-core copy is also updated if possible.  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 first form of the command is used to examine the label
       on the named disk drive (e.g. hp0 or /dev/rhp0c).  It will
       display  all  of  the parameters associated with the drive
       and its partition layout.  Unless the --r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 --rr flag is given, the  label  from  the
       raw  disk will be displayed rather than the in-core label.

       The second form of the command, with the --ww flag, is  used
       to  write  a  standard label on the designated drive.  The
       required arguments  to  _d_i_s_k_l_a_b_e_l  are  the  drive  to  be
       labelled  (e.g.  hp0),  and the drive type as described in
       the _d_i_s_k_t_a_b(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 first optional argument is a pack identifica-
       tion string, up to 16 characters long.  The pack  id  must


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DISKLABEL(8)                                         DISKLABEL(8)


       be quoted if it contains blanks.  If the --rr flag is given,
       the disk sectors containing the label and  bootstrap  will
       be  written directly, otherwise the existing label will be
       updated in place without modifying the bootstrap.  If  the
       disk  does  not  already have a label, the --rr flag must be
       used.  In either  case,  the  kernel's  in-core  label  is
       replaced.

       Alternate versions of the bootstrap files may be specified
       after the pack identifier.  If an alternate  bootstrap  is
       not  specified,  the standard bootstrap will be used.  The
       bootstrap programs are located in _/_u_s_r_/_m_d_e_c.  The names of
       the  bootstrap programs may be specified in _d_i_s_k_t_a_b(5); if
       not specified, the default names are of the form _b_a_s_e_n_a_m_e_-
       boot for the primary (block 0) bootstrap, and boot_b_a_s_e_n_a_m_e
       for the secondary (block  1-15)  bootstrap;  for  example,
       /usr/mdec/hpboot  and  /usr/mdec/boothp if the disk device
       is hhpp00.

       An existing disk label may be edited by using the --ee flag.
       The  label  is  read  from  the  in-core  kernel  copy, or
       directly from the disk if the --rr flag is also given.   The
       label  is  formatted  and  then  supplied to an editor for
       changes.  If no editor is specified in an EDITOR  environ-
       ment variable, _v_i(1) is used.  When the editor terminates,
       the formatted label is reread and used to rewrite the disk
       label.

       With the --RR flag, _d_i_s_k_l_a_b_e_l 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 ##
       and newline.  If the --rr option is also  given,  a  block-0
       bootstrap  is  installed  on machines that use one; either
       the disktype or the names of the bootstrap files  must  be
       specified on such machines.

       Finally,  the  --NNWW flags for _d_i_s_k_l_a_b_e_l explicitly disallow
       and allow, respectively, writing of the pack label area on
       the selected disk.

FFIILLEESS
       /etc/disktab
       /usr/mdec/_x_xboot
       /usr/mdec/boot_x_x

SSEEEE AALLSSOO
       disktab(5), disklabel(5)

DDIIAAGGNNOOSSTTIICCSS
       The  kernel  device  drivers  will not allow the size of a
       disk partition to be decreased or the offset of  a  parti-
       tion  to be changed while it is open.  Some device drivers


                          June 24, 1990                         2


DISKLABEL(8)                                         DISKLABEL(8)


       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  parti-
       tion,  and  the second setting the label on the new parti-
       tion while shrinking the ``a'' partition.

BBUUGGSS
       When a disk name is given without  a  full  pathname,  the
       constructed  device  name  uses the ``c'' partition on the
       vax and the ``a'' partition on the tahoe.


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