Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

#### BIOPG

Prolog

Control Block Contents
BIOPG DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### BIOPG Prolog

     NAME       : HCPBIOPG
     DESCRIPTION: DASD Block I/O Storage Management Block
     DSECT      : BIOPG aka BIOBG
     FUNCTION   : Contains header information and room to
                  allocate I/O related control blocks for
                  DIAGNOSE 18, A4, 250 and *BLOCKIO.
     LOCATED BY : BIOPGNXT and BIOPGPRV links the list together
                  (caller must remember the start)
     CREATED BY : HCPDPSGP
     DELETED BY : HCPDPSRP, HCPDPSCU
     COMMENTS   : This block comes in two sizes: 2040 bytes and
                  4088 bytes.  The size chosen is determined by
                  the length of the request.
                  The BIOPG consists of a header and available storage.
                  Its used as a source for control blocks.  The HCPDPCUT
                  macro will obtain storage from the BIOPG to create
                  control blocks such as the IORBK and DVIOPs. This avoids
                  the need to call HCPFREE for each needed control block.
                  When the storage in one BIOPG is used up, another is
                  obtained and linked to the previous using BIOPGNXT.

#### BIOPG Control Block Content

#### BIOPG DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      BIOPG          DASD Block I/O Storage Management Block
    0000    0 Signed       4 BIOPGNXT       Pointer to the next BIOPG block
                                            (0 if no more)
    0004    4 Signed       4 *              Reserved for IBM use
    0008    8 Signed       4 BIOPGAV        Pointer to the next available
                                            storage location
    000C   12 Signed       4 BIOPGEND       Address of BIOBGEND/BIOPEND
    0010   16 Bitstring 2024 BIOPDATA       Size of data area
              000007F8       BIOPEND        * Byte following end of BIOPG
              000000FF       BIOPGDWS       (((*-BIOPG)+7)/8) Size in
                                            doublewords
          Redefine the data area for the larger sized block.
          This larger block has a separate entry in the CBITABLE
          and uses BIOBG as it's ID.
    0010   16 Bitstring 4072 BIOBDATA       Size of data area
              00000FF8       BIOBGEND       * Byte following end of BIOBG
              000001FF       BIOBGDWS       (((*-BIOPG)+7)/8) Size in
                                            doublewords

#### BIOPG Storage Layout

    *** BIOPG - DASD Block I/O Storage Management Block
    *
    *     +---------------------------+---------------------------+
    *   0 |         BIOPGNXT          |///////////////////////////|
    *     +---------------------------+---------------------------+
    *   8 |         BIOPGAV           |         BIOPGEND          |
    *     +---------------------------+---------------------------+
    *  10 |                                                       |
    *     =                       BIOPDATA                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * 7F8
    *
    *** BIOPG - DASD Block I/O Storage Management Block

    *** Overlay for BIOPDATA in BIOPG
    *
    *     +-------------------------------------------------------+
    *  10 |                                                       |
    *     =                       BIOBDATA                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    * FF8
    *
    *** Overlay for BIOPDATA in BIOPG

#### BIOPG Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    BIOBDATA       0010
    BIOBGDWS       0010 000001FF
    BIOBGEND       0010 00000FF8
    BIOPDATA       0010
    BIOPEND        0010 000007F8
    BIOPGAV        0008
    BIOPGDWS       0010 000000FF
    BIOPGEND       000C
    BIOPGNXT       0000

This information is based on z/VM V6R1.0. Last updated on 18 Feb 2010 at 08:26:46 EDT.
Copyright IBM Corporation, 1990, 2008