OSIBK | Back to Index page

| Prolog Control Block Contents OSIBK DSECT Storage Layout Cross Reference (Contains links to field and bit definitions) |
Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

OSIBK Prolog | Top of page

     NAME       : HCPOSIBK
     DESCRIPTION: OS Info
     DSECT      : OSIBK
     FUNCTION   : The OSIBK describes the contents of the OS Info data area
                  which is a data interface to stand-alone dump. This is a
                  singleton data structure.
     LOCATED BY : HCPDMOSI - allocated in nucleus. IPL sets the location.
                  PFXOSIAD - in each PFXPG as well as absolute page 0. The
                  absolute page 0 location is the one used by
                  stand-alone dump to locate the data area.
                  For SAPL, located in a page of storage within HCPSAL.
                  For DDR, located in a page of storage within HCPDDR.
     CREATED BY : Allocated in CP nucleus and initialized in stages during
                  CP initialization. Never changed after IPL. See HCPDMO
                  for details of data area initialization.
                  For SAPL, the OSIBK is located in a page of storage
                  within HCPSAL and initialized early during its
                  processing.  In most cases, the OSIBK is overlaid by
                  the module being loaded during the end of SAPL's
                  processing.  Whether the overlay occurs depends on the
                  load origin that was requested.
                  For DDR, the OSIBK located in a page of storage within
                  HCPDDR and initialized early during its processing if
                  DDR is running stand-alone.  It is never changed after
                  being initialized.
     DELETED BY : Never deleted.
     REFERENCES : None
     SERIALIZED : CP initialization (uni-processor).
                  SAPL and DDR run entirely in uni-processor mode.
     RELOCATION CONSIDERATIONS : None
     COMPATIBILITY AND MIGRATION CONCERNS : - The format and content of the OS Info is determined by
                  the level of the stand-alone dump function supported by
                  the VM release.
                  - The level of the stand-alone dump support is determined
                  by the level of VLP distributed with VM.
                  - The OSIVERMJ and OSIVERMN fields document the version
                  and thus the format and content of the OS Info area.
                  OSIVERMJ (version_major) -
                  - For incompatible interface changes, for example when
                  new mandatory fields are introduced to the OS Info
                  structure, the major version will be increased.  When
                  the stand-alone dump utility finds an OS info structure
                  that has a higher version number, stand-alone dump will
                  stop with a disabled wait PSW.  Therefore when a major
                  version update is done, VM users have to prepare their
                  dump disks with the new version of the stand-alone dump
                  utility.
                  OSIVERMN (version_minor) -
                  - For compatible interface changes, for example when new
                  optional fields are introduced to the OS info
                  structure, the minor version will be increased.  When
                  the stand-alone dump utility finds an OS info structure
                  that has a higher version number, stand-alone dump will
                  ignore the new optional features and will do everything
                  that was defined for its own lower version number.
                  - version_minor resets to 1 when version_major increases
     NOTES      : - Must be allocated on a page boundary.
                  - Must be 4K in length.
                  - Refer to the design document "RAS1211 Support for
                  stand-alone kdump" from IBM LTC.  That document defines
                  the format and content of OS Info.

OSIBK Control Block Content | Top of page

     OSIBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      OSIBK          OS Info
          Now define the OSIBK.
    0000    0 Bitstring    8 OSIMAGIC       Magic number for OS Info.
                                            Contains ascii string of
                                            'OSINFOSZ'
    0008    8 Signed       4 OSICSUM        Checksum for OS Info structure
                                            calculated for OS Info starting
                                            at OSIVERMJ to the end of the
                                            page.
    000C   12 Signed       2 OSIVERMJ       Version_major - see prolog.
    000E   14 Signed       2 OSIVERMN       Version_minor - see prolog.
    0010   16 Address      8 OSICKADD       Crashkernel_addr - absolute addr
                                            of crashkernel memory which must
                                            have megabyte alignment. See
                                            HCPDMO for a description of its
                                            usage.
          Limit the requirement for RSMBK reference to HCPDMO.
    0018   24 Address      8 OSICKSIZ       Crashkernel_size - bytes of
                                            crashkernel memory. Size must be
                                            a multiple of whole megabytes.
          Don't reference HCPDMOVC when not part of CP nucleus.
    0020   32 Address      8 OSIVCADD       Absolute address of vmcoreinfo.
    0028   40 Signed       8 OSIVCSIZ       Size in bytes of vmcoreinfo.
                                            Vmcoreinfo must not have a
                                            terminating zero.
    0030   48 Signed       4 OSIVCCSM       Checksum of vmcoreinfo structure.
                                            next 2 fields are not dword
                                            aligned by design.
    0034   52 Bitstring    8 OSIRBADD       Absolute address of Diag x'308'
                                            re-IPL block. (unused)
    003C   60 Bitstring    8 OSIRBSIZ       Size of Diag x'308' re-IPL block.
                                            (unused)
    0044   68 Signed       4 OSIRBCSM       Checksum of Diag x'308' re-IPL
                                            block. (unused)
          HCPOSIBK is 4K in length.
    0048   72 Bitstring    1 OSIRESRV (4024)
                                            Reserved for IBM use
              00000FF4       OSICSUML       *-OSIVERMJ Length of area the
                                            OSICSUM value is calculated for.
              00000200       OSISIZE        (*-OSIBK+7)/8 Size in double
                                            words
              00001000       OSIBSIZE       OSISIZE*8 Size in bytes

OSIBK Storage Layout | Top of page

    *** OSIBK - OS Info
    *
    *     +-------------------------------------------------------+
    *   0 |                       OSIMAGIC                        |
    *     +---------------------------+-------------+-------------+
    *   8 |         OSICSUM           |  OSIVERMJ   |  OSIVERMN   |
    *     +---------------------------+-------------+-------------+
    *  10 |                       OSICKADD                        |
    *     +-------------------------------------------------------+
    *  18 |                       OSICKSIZ                        |
    *     +-------------------------------------------------------+
    *  20 |                       OSIVCADD                        |
    *     +-------------------------------------------------------+
    *  28 |                       OSIVCSIZ                        |
    *     +---------------------------+---------------------------+
    *  30 |         OSIVCCSM          |        OSIRBADD-          |
    *     +---------------------------+---------------------------+
    *  38 |          -(034)           |        OSIRBSIZ-          |
    *     +---------------------------+---------------------------+
    *  40 |          -(03C)           |         OSIRBCSM          |
    *     +---------------------------+---------------------------+
    *  48 |                                                       |
    *     =                       OSIRESRV                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *1000
    *
    *** OSIBK - OS Info

OSIBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    OSIBSIZE       0048 00001000
    OSICKADD       0010
    OSICKSIZ       0018
    OSICSUM        0008
    OSICSUML       0048 00000FF4
    OSIMAGIC       0000
    OSIRBADD       0034
    OSIRBCSM       0044
    OSIRBSIZ       003C
    OSIRESRV       0048
    OSISIZE        0048 00000200
    OSIVCADD       0020
    OSIVCCSM       0030
    OSIVCSIZ       0028
    OSIVERMJ       000C
    OSIVERMN       000E

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:29:27 EDT.
Copyright IBM Corporation, 1990, 2020