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OpenVMS Undocumented Features


This is the most complete collection of undocumented features we can find for OpenVMS. Some of these have been around since the time when it was called VMS while others are more current and have been added to OpenVMS V8.n. These features:

  • Are NOT documented (if they were, they wouldn't belong here)
  • Are NOT supported by PARSEC Group or HP
  • Are NOT guaranteed to work
  • May NOT exist in all versions of OpenVMS; past, present and future
  • Are subject to change, removal, enhancement or being documented at the whim of OpenVMS engineering
  • May be fun to know the next time you play OpenVMS trivial pursuit
  • May help you get your job done easier and faster
  • May help you impress your boss with your knowledge of the obscure

Analyzing BACKUP save-sets

Adding the /ANALYZE qualifier to the BACKUP /LIST command causes BACKUP to provide a structural dump of the save set.

$ backup login.com login.bck/save
$ backup /list /analyze login.bck /save
Listing of save set(s)

Block header
  SIZE      = 256
  OPSYS     = 2048
  SUBSYS    = 1
  APPLIC    = 1
  NUMBER    = 1
  STRUCLEV  = 0101
  VOLNUM    = 1
  CRC       = 7362C94D
  BLOCKSIZE = 32256
  NOCRC     = False
  SSNAME    = "LOGIN.BCK"
  FID       = 0,0,0
  DID       = 0,0,0
  FILENAME  = ""
  ATTRIB    = 0000000000000000
  FILESIZE  = 0

Record header
  RSIZE         = 176 = %X'00B0'
  RTYPE         = SUMMARY (1)
  FLAGS         = %X'00000000'
  ADDRESS       = 0
  BLOCKFLAGS    = %X'0000'

    STRUCLEV = 0101
    SIZE =   9, TYPE = SSNAME
      "LOGIN.BCK"
    SIZE =  31, TYPE = COMMAND
      "BACKUP LOGIN.COM LOGIN.BCK/SAVE"
    SIZE =  12, TYPE = USERNAME
      "WILLIAMS    "
    SIZE =   4, TYPE = USERUIC
      [7,6]
    SIZE =   8, TYPE = DATE
       7-MAR-2007 22:54:00.04
    SIZE =   2, TYPE = OPSYS
      0800
    SIZE =   4, TYPE = SYSVER
      "V8.3"
    SIZE =   9, TYPE = NODENAME
      "_CLASS2::"
    SIZE =   4, TYPE = SIR
      80000000
    SIZE =  12, TYPE = DRIVEID
      "_$22$DKA300:"
    SIZE =   4, TYPE = BACKVER
      "V8.3"
    SIZE =   4, TYPE = BLOCKSIZE
      32256
    SIZE =   2, TYPE = XORSIZE
      10
    SIZE =   2, TYPE = BUFFERS
      1238

Record header
  RSIZE         = 256 = %X'0100'
  RTYPE         = FILE (3)
  FLAGS         = %X'00000000'
  ADDRESS       = 0
  BLOCKFLAGS    = %X'0000'

    STRUCLEV = 0101
    SIZE =  22, TYPE = FILENAME
      "[WILLIAMS]LOGIN.COM;55"
    SIZE =   2, TYPE = STRUCLEV
      0201
    SIZE =   6, TYPE = FID
      28639,3,1
    SIZE =   4, TYPE = FILESIZE
      35
    SIZE =   4, TYPE = UIC
      [7,6]
    SIZE =  32, TYPE = RECATTR
      0000000000000000000000000000000000000168000400000023000000590202
    SIZE =   6, TYPE = BACKLINK
      19429,3,0
    SIZE =   2, TYPE = FPRO
      System:RWED, Owner:RWED, Group:RE, World:
    SIZE =   2, TYPE = RPRO
      System:RWUD, Owner:RWUD, Group:RWUD, World:RWUD
    SIZE =   1, TYPE = ACLEVEL
      00
    SIZE =   4, TYPE = UCHAR
      00000300
    SIZE =   2, TYPE = VERLIMIT
      32767
    SIZE =   1, TYPE = JNL_FLAGS
      00
    SIZE =   1, TYPE = RU_ACTIVE
      00
    SIZE =   4, TYPE = HIGHWATER
      5
    SIZE =   2, TYPE = REVISION
      1
    SIZE =   8, TYPE = CREDATE
      23-JAN-2007 16:40:36.66
    SIZE =   8, TYPE = REVDATE
      23-JAN-2007 16:40:36.72
    SIZE =   8, TYPE = EXPDATE
      17-NOV-1858 00:00:00.00
    SIZE =   8, TYPE = BAKDATE
      17-NOV-1858 00:00:00.00
    SIZE =   4, TYPE = DIR_UIC
      [7,6]
    SIZE =   2, TYPE = DIR_FPRO
      System:RWE, Owner:RWE, Group:RE, World:E
    SIZE =   2, TYPE = DIR_VERLIM
      32767
    SIZE =  12, TYPE = ACLSEGMENT
      (IDENTIFIER=[5,12],ACCESS=NONE)


Record header
  RSIZE         = 2048 = %X'0800'
  RTYPE         = VBN (4)
  FLAGS         = %X'00000000'
  ADDRESS       = 1
  BLOCKFLAGS    = %X'0000'

Record header
  RSIZE         = 256 = %X'0100'
  RTYPE         = FILE (3)
  FLAGS         = %X'00000000'
  ADDRESS       = 0
  BLOCKFLAGS    = %X'0000'

    STRUCLEV = 0101
    SIZE =  22, TYPE = FILENAME
      "[WILLIAMS]LOGIN.COM;54"
    SIZE =   2, TYPE = STRUCLEV
      0201
    SIZE =   6, TYPE = FID
      20021,1,1
    SIZE =   4, TYPE = FILESIZE
      35
    SIZE =   4, TYPE = UIC
      [7,6]
    SIZE =  32, TYPE = RECATTR
      00000000000000000000000000000000000001E2000400000023000000590202
    SIZE =   6, TYPE = BACKLINK
      19429,3,0
    SIZE =   2, TYPE = FPRO
      System:RWED, Owner:RWED, Group:RE, World:
    SIZE =   2, TYPE = RPRO
      System:RWUD, Owner:RWUD, Group:RWUD, World:RWUD
    SIZE =   1, TYPE = ACLEVEL
      00
    SIZE =   4, TYPE = UCHAR
      00000300
    SIZE =   2, TYPE = VERLIMIT
      32767
    SIZE =   1, TYPE = JNL_FLAGS
      00
    SIZE =   1, TYPE = RU_ACTIVE
      00
    SIZE =   4, TYPE = HIGHWATER
      5
    SIZE =   2, TYPE = REVISION
      1
    SIZE =   8, TYPE = CREDATE
       2-OCT-2006 11:21:13.80
    SIZE =   8, TYPE = REVDATE
       2-OCT-2006 11:21:13.84
    SIZE =   8, TYPE = EXPDATE
      17-NOV-1858 00:00:00.00
    SIZE =   8, TYPE = BAKDATE
      17-NOV-2006 09:58:24.85
    SIZE =   4, TYPE = DIR_UIC
      [7,6]
    SIZE =   2, TYPE = DIR_FPRO
      System:RWE, Owner:RWE, Group:RE, World:E
    SIZE =   2, TYPE = DIR_VERLIM
      32767
    SIZE =  12, TYPE = ACLSEGMENT
      (IDENTIFIER=[5,12],ACCESS=NONE)


Record header
  RSIZE         = 2048 = %X'0800'
  RTYPE         = VBN (4)
  FLAGS         = %X'00000000'
  ADDRESS       = 1
  BLOCKFLAGS    = %X'0000'

Record header
  RSIZE         = 27120 = %X'69F0'
  RTYPE         = NULL (0)
  FLAGS         = %X'00000000'
  ADDRESS       = 0
  BLOCKFLAGS    = %X'0000'


End of save set


RADCHECK Utility

The RADCHECK utility may be used on RAD (Resource Affinity Domain) based systems to get or change information about how OpenVMS is handling RADs. The utility resides in the SYS$TEST directory and provides some help when provided the ? or "help" parameter.

$ mcr sys$test:radcheck ?
This program checks the locality of memory on an OpenVMS system.

You can specify that you want it to check a particular process, or
you can specify all process pages, all system pages, or all global pages.

This same program can also give information about RAD-based process
scheduling.  Specify 'sched' as the first argument to switch to this mode

Usage:

? or -help      Print this message including general informative info
sched           Switch to scheduler mode.  Say 'radcheck sched help' for more.

What page tables to look at:

-allprocs       Search pages belonging to all processes
-noprocs        Do not search pages belonging to processes
-(no)system     (Do not) search the system page tables
-(no)global     (Do not) search the process global page table*

Summary switches:

-all            Turn on all the above switches.  Can be followed by turn-off
                commands
-none           Turn off all the above switches.  Can be followed by turn-on
                commands

Modifiers:

-process n      Search pages belonging to the process specified by process ID n
                (0=this process)
-pid n          Identical to -process n
-sysrad n       For -system, look at replicated system pages from RAD n
                (-2=pick a RAD, -1=do nothing special)
-timeout n      For async process operations, give up after waiting n seconds

Default switches:  -all -sysrad -2 -timeout 30

*Note: The global page table display counts each global page once regardless of
       how many processes may be mapping it.  The process displays count a
       global page once for each time it is mapped.


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Please enjoy these features at your own risk. If you are aware of other features in OpenVMS which are currently undocumented, you may use our inquiry form to inform us. We may then add it to our list.