DS4LABEL | Back to Index page

| Prolog Control Block Contents DS4LABEL 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.

DS4LABEL Control Block Content | Top of page

     DS4LABEL DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      DS4LABEL       Mapping for VTOC DSCB's
    0000    0 Character   44 DS4DSNAM       Data set name For Format 4 DSCB,
                                            DS4IDFMT = c'4'.
    002C   44 Character    1 DS4IDFMT       Format identifier
    002D   45 Bitstring    5 DS4HPCHR       Highest address of a format 1
                                            DSCB
    0032   50 Bitstring    2 DS4DSREC       Number of available DSCBs
    0034   52 Bitstring    4 DS4HCCHH       CCHH of next available alternate
                                            trk
    0038   56 Bitstring    2 DS4NOATK       Number of remaining alternate
                                            trks
    003A   58 Bitstring    1 DS4VTOCI       VTOC indicators
    003B   59 Bitstring    1 DS4NOEXT       Number of extents in the VTOC
    003C   60 Bitstring    2 *              Reserved
    003E   62 Bitstring   14 DS4DEVCT (0)   Device constants
    003E   62 Bitstring    4 DS4DEVSZ       Device size
    0042   66 Bitstring    2 DS4DEVTK       Device track length
    0044   68 Bitstring    2 DS4DEVOV (0)   Keyed record overhead
    0044   68 Bitstring    1 DS4DEVI        non-last keyed record overhead
    0045   69 Bitstring    1 DS4DEVL        last keyed record overhead
    0046   70 Bitstring    1 DS4DEVK        Non-keyed record overhead differ.
    0047   71 Bitstring    1 DS4DEVFG       Flag byte
    0048   72 Bitstring    2 DS4DEVTL       Device tolerance
    004A   74 Bitstring    1 DS4DEVDT       Number of DSCBs per track
    004B   75 Bitstring    1 DS4DEVDB       Number of directory blocks per
                                            track
    004C   76 Bitstring    8 DS4AMTIM       VSAM time stamp
    0054   84 Bitstring    3 DS4AMCAT (0)   VSAM catalog indicator
    0054   84 Bitstring    1 DS4VSIND       VSAM indicators
    0055   85 Bitstring    2 DS4VSCRA       Relative track location of the
                                            CRA
    0057   87 Bitstring    8 DS4R2TIM       VSAM volume/catalog match time
                                            stamp
    005F   95 Bitstring    5 *              Reserved
    0064  100 Bitstring    5 DS4F6PTR       Pointer to first format 6 DSCB
    0069  105 Bitstring   10 DS4VTOCE       VTOC extent description
    0073  115 Bitstring   25 *              Reserved
              0000008C       DS4END         *
             DSECT for VTOC DSCB Format 5 Records
          Bit mappings of unuseful flag bytes are not shown.
          Offsets for all DS5LABEL are based from start of key, not
          start of data.

DS4LABEL Storage Layout | Top of page

    *** DS4LABEL - Mapping for VTOC DSCB's
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       DS4DSNAM                        =
    *     |                           +------+--------------------+
    *  28 |                           |:IDFMT|     DS4HPCHR-      |
    *     +-------------+-------------+------+--------------------+
    *  30 |   -(02D)    |  DS4DSREC   |         DS4HCCHH          |
    *     +-------------+------+------+-------------+-------------+
    *  38 |  DS4NOATK   |:VTOCI|:NOEXT|/////////////| DS4DEVSZ-   |
    *     +-------------+------+------+------+------+------+------+
    *  40 |   -(03E)    |  DS4DEVTK   |:DEVI |:DEVL |:DEVK |:DEVFG|
    *     +-------------+------+------+------+------+------+------+
    *  48 |  DS4DEVTL   |:DEVDT|:DEVDB|        DS4AMTIM-          |
    *     +-------------+------+------+------+-------------+------+
    *  50 |          -(04C)           |:VSIND|  DS4VSCRA   |(057)-|
    *     +---------------------------+------+-------------+------+
    *  58 |                   -DS4R2TIM                    |//////|
    *     +---------------------------+--------------------+------+
    *  60 |///////////////////////////|        DS4F6PTR-          |
    *     +------+--------------------+---------------------------+
    *  68 |-(064)|                   DS4VTOCE                     |
    *     +------+             +----------------------------------+
    *     |                    |//////////////////////////////////|
    *     +--------------------+//////////////////////////////////|
    *  78 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////+---------------------------+
    *     |///////////////////////////| 8C
    *     +---------------------------+
    *
    *** DS4LABEL - Mapping for VTOC DSCB's

DS4LABEL Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    DS4AMCAT       0054
    DS4AMTIM       004C
    DS4DEVCT       003E
    DS4DEVDB       004B
    DS4DEVDT       004A
    DS4DEVFG       0047
    DS4DEVI        0044
    DS4DEVK        0046
    DS4DEVL        0045
    DS4DEVOV       0044
    DS4DEVSZ       003E
    DS4DEVTK       0042
    DS4DEVTL       0048
    DS4DSNAM       0000
    DS4DSREC       0032
    DS4END         0073 0000008C
    DS4F6PTR       0064
    DS4HCCHH       0034
    DS4HPCHR       002D
    DS4IDFMT       002C
    DS4NOATK       0038
    DS4NOEXT       003B
    DS4R2TIM       0057
    DS4VSCRA       0055
    DS4VSIND       0054
    DS4VTOCE       0069
    DS4VTOCI       003A

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:27:56 EDT.
Copyright IBM Corporation, 1990, 2020