1 02/13/85 init_vol
  2 
  3 Syntax as a command:  init_vol volume_name drive_name {-control_arg}
  4 
  5 
  6 Function:  writes the label of a new physical volume and sets up its
  7 VTOC and volume map.  This operation destroys any previous contents of
  8 the physical volume.  This command can be used in ring 1 or ring 4.  It
  9 is also automatically entered when a cold boot is done to initialize
 10 the RPV.
 11 
 12 
 13 Arguments:
 14 volume_name
 15    is the name of a physical volume.
 16 drive_name
 17    has the form <subsys>_<nn>, e.g., dska_02.
 18 
 19 
 20 Control arguments:
 21 -special
 22    enters dialogue with the user.  The -special control argument is
 23    recommended for all RLV volumes.
 24 -copy
 25    initializes a copy of an already accepted physical volume (-copy
 26    also enters dialogue with the user).
 27 -rlv
 28    specifies that the physical volume is to be registered as part of
 29    the root logical volume.  this control argument can be used only
 30    during a cold boot of the root physical volume at ring-1 initializer
 31    command level.
 32 
 33 
 34 Notes on special mode:  Special mode is entered when -special is given
 35 on an init_vol command line, when the rebuild_disk command is used, or
 36 when a cold boot of the RPV is done.  In special mode, the user may
 37 specify various parameters of the volume being initialized as other
 38 than their default values.  Special mode uses a request loop subsystem
 39 to allow entry of these parameters.  This includes the ability to
 40 specify the locations and extents of partitions.
 41 
 42 Defaults for volume initialized by init_vol or rebuild_disk command are
 43 no partitions and VTOC size constrained by average segment length of
 44 5.0.
 45 
 46 
 47 Defaults for RPV initialized by cold boot sequence are partitions laid
 48 out on pack as follows.
 49 
 50            partition        partition          low/high
 51              name       size (in records)     end of pack
 52 
 53            HC                 2500            low
 54            CONF                  4            low
 55            <paging region>    <all space not used by partitions>
 56            FILE                255            high
 57            BCE                2200            high
 58            LOG                 256            high
 59            DUMP               2000            high
 60            BOS                 270            high
 61            ALT              as needed         high
 62 
 63 
 64 VTOC size constrained by average segment length of 2.0
 65 
 66 For non-RPV packs belonging to the RLV, it is recommended that special
 67 mode be used to set an average segment length of 4.0 since directories,
 68 which reside on the RLV, are usually smaller than other segments.  A
 69 smaller average segment length increases the number of VTOC entries
 70 (VTOCES) on the pack.  Since it is easier to make the VTOC bigger than
 71 to make it smaller, the recommended procedure is to start with 4.0 as
 72 an average segment length.  If more VTOCES are needed later, the
 73 rebuild_disk command can be used to define them.
 74 
 75 When using volume backup to recover the contents of a disk pack, make
 76 sure there are at least as many available records and total VTOC
 77 entries as there were on the physical volume before it was damaged.
 78 
 79 
 80 Notes on request loop of init_vol:  The following request lines may be
 81 typed when init_vol is invoked with the -special control argument,
 82 when the rebuild_disk command is being used, or within the cold boot
 83 sequence.
 84 asl FFF.FF, avg FFF.FF
 85    specifies the average segment length, which is used to determine the
 86    VTOC size.  As partitions are defined, the VTOC size is adjusted to
 87    maintain a VTOC entry to free page ratio producing this average
 88    segment length.  When operating in this mode (the default, with
 89    average segment length = 5.0), the parameters are said to be
 90    constrained by average segment length.
 91 default
 92    causes all parameters to be reset to their cold boot defaults,
 93    including the list of partitions.  This request is only valid within
 94    the cold boot sequence.
 95 
 96 
 97 end
 98    causes the command init_vol or rebuild_disk to proceed using the
 99    parameters as they stand at this point.
100 help
101    lists all requests available within the init_vol request loop.
102 lace N
103    specifies physical address assignment interlace; i.e., specifies
104    that the system should try to place the pages of a segment N disk
105    records apart on the target disk.  The default value for N is 2.
106    This request is only valid in the rebuild_disk command.
107 
108 
109 list
110    causes the current parameters to be listed, including partition
111    data, VTOC size, number of VTOC entries and effective average
112    segment length.  Issuing other requests causes these parameters to
113    change.  When the request loop is entered, a list request is
114    performed automatically.
115 nvtoce N
116    specifies the VTOC size by the number of VTOC entries to be created.
117    As five VTOC entries occupy each page, this number is rounded up to
118    the next five before use.
119 
120 
121    This constrains parameters by VTOC size.
122 part name hilow size
123    where name is a 4-character or fewer partition name, hilow is either
124    "high" or "low", and size is the partition size in records, defines
125    a partition to be allocated on the pack.  The hilow argument
126    specifies which end of the pack, with respect to device address, the
127    partition shall be allocated.  Successive requests for "high"
128    partitions receive successively lower addresses, and successive
129    requests for "low" partitions receive successively higher addresses.
130    Partitions may not be redefined without issuing the "startover"
131    request.
132 quit
133    causes the command init_vol or rebuild_disk to be aborted, without
134    initializing or rebuilding any disks.  This request is not valid
135    within the cold boot sequence.
136 
137 
138 startover
139    causes all parameters to be reset to their defaults (init_vol
140    command defaults, not cold boot defaults).  In particular, no
141    partitions are defined, even in the cold boot environment.
142 vtoc N
143    specifies the total number of pages to be allocated for the volume
144    header and volume table of contents (VTOC).  All other space on the
145    pack is available for paging and partitions.  When the "vtoc" or
146    "nvtoce" request is given, the parameters are said to be constrained
147    by VTOC size, and average segment length varies as partitions are
148    defined.
149 
150 
151 Notes:  The init_vol command queries the user before destroying the
152 label of any pack that appears to be a validly labeled pack.  A message
153 giving the pack's physical volume name and time of last use is
154 displayed.
155 
156 The init_vol command takes about 90 seconds for a model M400 disk.