1 02/27/85 scavenge_vol
 2 
 3 Syntax as a command:  scavenge_vol {pvname} {-control_args}
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 5 
 6 Syntax as an active function:  [scavenge_vol {pvname} {-control_args}]
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 8 
 9 Function:  invokes the Scavenger to scavenge one or more physical
10 volumes.  The Scavenger examines and validates VTOCEs, deletes
11 per-process and per-bootload VTOCEs from previous bootloads, recovers
12 lost VTOCEs, recovers lost records, and checks for reused addresses
13 (two VTOCES claiming the same record address).  See the Multics System
14 Maintenance Procedures manual, Order No.  AM81, for a description of
15 scavenging.
16 
17 If no control arguments are specified, no default actions are taken.
18 
19 The initializer command "x scav" logs in a daemon to perform a scavenge
20 using the scavenge_vol command.
21 
22 
23 Arguments:
24 pvname
25    is the name of the physical volume to be scavenged.  It must be part
26    of a mounted logical volume.  This argument is required unless the
27    -all or -lv control argument is specified.
28 
29 
30 Control arguments:
31 -all, -a
32    scavenges, in turn, all mounted physical volumes.
33 -auto
34    controls scavenging of physical volumes when the -lv or -all control
35    argument is specified.  When this option is used, those physical
36    volumes with volume inconsistencies are scavenged.
37 -check
38    validates the command control arguments and prints a list of
39    physical volumes that would be scavenged as a result of the command
40    line input, but does not actually perform the scavenge.
41 -debug
42    should be used only by systems programmers debugging the Scavenger.
43    It causes additional information to be printed on the bootload
44    console during the scavenge.
45 
46 
47 -dump
48    records the VTOCE image of any VTOCE found inconsistent into the
49    syserr log.  The image recorded is the VTOCE prior to any correction
50    by the Scavenger.
51 -lv lvname
52    scavenges, in turn, all physical volumes belonging to the logical
53    volume specified by lvname.  The logical volume must be mounted.
54 -no_optimize, -nopt
55    disables optimization of Scavenger processing.  This causes the
56    Scavenger to take longer, but reduces its effect on other users of
57    the system.  With this option, VTOCE read-ahead is disabled, and the
58    Scavenger periodically lowers its traffic control priority.
59 
60 
61 Access required:  Access to the hphcs_ gate is required.
62 
63 
64 Notes:  The scavenge of each volume is done entirely in ring 0.  Any
65 error messages are recorded into the syserr log.  It is possible to
66 interrupt a scavenge of a volume with the QUIT key, but it cannot be
67 restarted afterwards with the start or program_interrupt commands.
68 
69 When the scavenge_vol command is invoked as an active function, it
70 returns a list of physical volumes that would be scavenged, separated
71 by spaces.  The -check control argument is the default for active
72 function usage, i.e., scavenging is not done.