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

#### LRDA

Prolog

Control Block Contents
LRDA DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### LRDA Prolog

     Name       : HCPLRDA
     Description: Locate Record data area
     DSECT      : LRDA
     Function   : Maps the contents of the Locate Record data
                  area.
     Located by :
                  HCCWADDR - The Locate Record CCW data address field
                  contains the address of the locate
                  record data area.
     Created by :
                  Storage for this control block cannot be
                  specifically allocated/deallocated using
                  HCPGETST/HCPRELST.
                  Paging I/O manager -
                  The data area resides in the HCPPIOBK which
                  is allocated by HCPRDA.
                  Track cache manager -
                  Data area is part of a larger free storage
                  area used to build ECKD channel programs
                  which is allocated in modules HCPFMU/HCPFMP.
     Deleted by :
                  Storage for this control block cannot be
                  specifically allocated/deallocated using
                  HCPGETST/HCPRELST.
                  Paging I/O manager -
                  The data area resides in the HCPPIOBK which
                  is allocated by HCPRDD.
                  Track cache manager -
                  Data area is part of a larger free storage
                  area used to build ECKD channel programs
                  which is deallocated in modules HCPFMU/HCPFMP.
     Serialized :
                  Paging I/O manager -
                  EXPLCKFG - The paging I/O manager uses the exposure
                  block lock to serialize this data area.
                  Track cache manager -
                  TCMTSLK  - Track cache lock
     Comments   :
                  Paging I/O manager -
                  The Locate Record data area resides in the
                  HCPPIOBK. Each Locate Record CCW address field
                  contains the address of the Locate Record data
                  area within that PIOBK.
                  Track cache manager -
                  None

#### LRDA Control Block Content

#### LRDA DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      LRDA           Locate Record data area
    0000    0 Bitstring   16 LRDAREA (0)    Locate record data area
                 Byte 0 (Operation byte)
                 Although defined as BITs, the contents of the
                 operation byte are, architecturally, multiple
                 codes.
    0000    0 Bitstring    1 LRDOP          Operation byte
              11.. ....      LRDOR          X'C0' LRDOR Operation byte, bits
                                            0 and 1 ------- Codes for use
                                            with LRDOR
              .... ....      LRDORCA        X'00' LRDORCA Orient on count
                                            area
              .1.. ....      LRDORHA        X'40' LRDORHA Orient on home
                                            address
              1... ....      LRDORDA        X'80' LRDORDA Orient on data area
              11.. ....      LRDORIX        X'C0' LRDORIX Orient on index
                                            -------
              ..11 1111      LRDOOC         X'3F' Operation byte, bits 2
                                            through 7 ------- Codes for use
                                            with LRDOOC
              .... ....      LRDOCOR        X'00' Orient
              .... ...1      LRDOCWD        X'01' Write data
              .... ..11      LRDOCFW        X'03' Format write
              .... .11.      LRDOCRD        X'06' Read data
              .... 1.11      LRDOCWT        X'0B' Write track
              .... 11..      LRDOCRT        X'0C' Read tracks
              ...1 .11.      LRDOCR         X'16' Read -------
                 Byte 1 (Auxiliary byte)
    0001    1 Bitstring    1 LRDAUX         Auxiliary byte
              1... ....      LRDAVTLF       X'80' LRDAVTLF Validate transfer
                                            length factor
              .... ...1      LRDARCS        X'01' LRDARCS Read count suffix
                 Byte 2 (Zeros)
    0002    2 Bitstring    1 LRDZEROS       Must be zeros
                 Byte 3 (Record count)
    0003    3 Bitstring    1 LRDRECCT       Record count
                 Bytes 4 through 7 (Seek address)
    0004    4 Bitstring    4 LRDSEEK (0)    Seek address (CCHH)
    0004    4 Bitstring    2 LRDSCC         CC of CCHH
    0006    6 Bitstring    2 LRDSHH         HH of CCHH
                 Bytes 8 through 12 (Search argument)
    0008    8 Bitstring    5 LRDSRCH (0)    Search argument (CCHHR)
    0008    8 Bitstring    2 LRDRCC         CC of CCHHR
    000A   10 Bitstring    2 LRDRHH         HH of CCHHR
    000C   12 Bitstring    1 LRDRR          R of CCHHR
                 Byte 13 (Sector number)
    000D   13 Bitstring    1 LRDSECT        Sector number
                 Bytes 14 and 15 (Transfer length factor)
    000E   14 Bitstring    2 LRDTLF         Transfer length factor
                 Length equates
              00000010       LRDBSIZE       *-LRDAREA Size of LRDA in bytes
              00000002       LRDSIZE        ((*-LRDAREA)+7)/8 Size of LRDA in
                                            DWs

#### LRDA Storage Layout

    *** LRDA - Locate Record data area
    *
    *     +------+------+------+------+-------------+-------------+
    *   0 |LRDOP |LRDAUX|:ZEROS|:RECCT|   LRDSCC    |   LRDSHH    |
    *     +------+------+------+------+------+------+-------------+
    *   8 |   LRDRCC    |   LRDRHH    |LRDRR |:SECT |   LRDTLF    |
    *     +-------------+-------------+------+------+-------------+
    *  10
    *
    *** LRDA - Locate Record data area

#### LRDA Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    LRDARCS        0001 01
    LRDAREA        0000
    LRDAUX         0001
    LRDAVTLF       0001 80
    LRDBSIZE       000E 00000010
    LRDOCFW        0000 03
    LRDOCOR        0000 00
    LRDOCR         0000 16
    LRDOCRD        0000 06
    LRDOCRT        0000 0C
    LRDOCWD        0000 01
    LRDOCWT        0000 0B
    LRDOOC         0000 3F
    LRDOP          0000
    LRDOR          0000 C0
    LRDORCA        0000 00
    LRDORDA        0000 80
    LRDORHA        0000 40
    LRDORIX        0000 C0
    LRDRCC         0008
    LRDRECCT       0003
    LRDRHH         000A
    LRDRR          000C
    LRDSCC         0004
    LRDSECT        000D
    LRDSEEK        0004
    LRDSHH         0006
    LRDSIZE        000E 00000002
    LRDSRCH        0008
    LRDTLF         000E
    LRDZEROS       0002

This information is based on z/VM V6R1.0. Last updated on 18 Feb 2010 at 08:49:03 EDT.
Copyright IBM Corporation, 1990, 2008