VLDPG | Back to Index page

| Prolog Control Block Contents VLDPG DSECT VLDBK DSECT VLDSEG 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.

VLDPG Control Block Content | Top of page

     VLDPG DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      VLDPG          VLAN Definition Block
    0000    0 Bitstring    1 VLDPGHDR (0)   VLDPG Header
    0000    0 Character    8 VLDPGID        Eye-catcher (CL8'HCPVLDBK')
    0008    8 Bitstring    4 VLDPGNXT       Next page DASD ASA
    000C   12 Signed       2 VLDPGAVL       Next available byte (offset)
    000E   14 Bitstring    2 *              Reserved for IBM use
              00000010       VLDPGHLN       *-VLDPGHDR Length of VLDPG header
    0010   16 Bitstring    1 VLDPGDAT (0)   Space for page data
          VLDBK - VLAN Device Extension.

     VLDBK DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      VLDBK          VLAN Definition Block
    0000    0 Bitstring    1 VLDHDR (0)     VLAN Extension Header
    0000    0 Signed       2 VLDVSEG        Offset to VLDSEG (VLDHDRLN)
    0002    2 Signed       2 VLDLEN         Length of VLDBK (total)
    0004    4 Character    8 VLDUSER        Userid/Profile
    000C   12 Signed       2 VLDVDEV        Virtual Device Number
    000E   14 Signed       2 VLDVIDCT       Total VLAN ID count
    0010   16 Signed       2 VLDSEGCT       Total segments defined
    0012   18 Signed       2 VLDSEGBL       VLDSEG length (in bytes)
    0014   20 Signed       4 * (0)          Note fullword alignment
              00000014       VLDHDRLN       *-VLDHDR Length of VLDBK header
    0014   20 Bitstring    1 VLDSPEC (16)   Space for VID segments
              000001A4       VLDBKLN        (*-VLDBK) VLDBK size (max) in
                                            bytes
              00000035       VLDBKSZ        (VLDBKLN+7)/8 VLDBK size (max) in
                                            doublewords
          VLDSEG - One VLAN segment (nnnn-mmmm).

     VLDSEG DSECT
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    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      VLDSEG         VLAN Definition Block
    0000    0 Signed       2 VLDLOW         Low end of a range
    0002    2 Signed       2 VLDHIGH        High end of a range
              00000004       VLDSEGLN       *-VLDSEG Length of one VID
                                            segment
          Associated definitions.
            VLDSGMAX = the maximum number of VLDSEG entries
                       allowed.
            VLDSGLIM = the total length of a VLDBK with the
                       maximum number of segments (VLDSGMAX).
          NOTES      :
            VLDSGLIM must be able to fit within VLDPGDAT on
            disk, and the maximum size of a free storage block
            when the VLDBK is in memory.
              00000064       VLDSGMAX       100 Maximum segment counts
              000001A4       VLDSGLIM       (VLDHDRLN+(VLDSGMAX*VLDSEGLN))
                                            Max VLDBK length

VLDPG Storage Layout | Top of page

    *** VLDPG - VLAN Definition Block
    *
    *     +-------------------------------------------------------+
    *   0 |                       VLDPGID                         |
    *     +---------------------------+-------------+-------------+
    *   8 |         VLDPGNXT          |  VLDPGAVL   |/////////////|
    *     +---------------------------+-------------+-------------+
    *
    *** VLDPG - VLAN Definition Block

    *** VLDBK - VLAN Definition Block
    *
    *     +-------------+-------------+---------------------------+
    *   0 |  VLDVSEG    |   VLDLEN    |         VLDUSER-          |
    *     +-------------+-------------+-------------+-------------+
    *   8 |          -(004)           |  VLDVDEV    |  VLDVIDCT   |
    *     +-------------+-------------+-------------+-------------+
    *  10 |  VLDSEGCT   |  VLDSEGBL   |                           |
    *     +-------------+-------------+                           |
    *     |                       VLDSPEC                         |
    *     |                           +---------------------------+
    *     |                           | 24
    *     +---------------------------+
    *
    *** VLDBK - VLAN Definition Block

    *** VLDSEG - VLAN Definition Block
    *
    *     +-------------+-------------+
    *   0 |   VLDLOW    |  VLDHIGH    | 4
    *     +-------------+-------------+
    *
    *** VLDSEG - VLAN Definition Block

VLDPG Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    VLDBKLN        0014 000001A4
    VLDBKSZ        0014 00000035
    VLDHDR         0000
    VLDHDRLN       0014 00000014
    VLDHIGH        0002
    VLDLEN         0002
    VLDLOW         0000
    VLDPGAVL       000C
    VLDPGDAT       0010
    VLDPGHDR       0000
    VLDPGHLN       000E 00000010
    VLDPGID        0000
    VLDPGNXT       0008
    VLDSEGBL       0012
    VLDSEGCT       0010
    VLDSEGLN       0002 00000004
    VLDSGLIM       0002 000001A4
    VLDSGMAX       0002 00000064
    VLDSPEC        0014
    VLDUSER        0004
    VLDVDEV        000C
    VLDVIDCT       000E
    VLDVSEG        0000

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:31:37 EDT.
Copyright IBM Corporation, 1990, 2020