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.