Programming Interface Information: This page documents intended Programming Interfaces that allow the customer to write programs to obtain the services of z/VM.

#### VRDCBLOK

Prolog

Control Block Contents
VRDCBLOK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### VRDCBLOK Prolog

     NAME       : VRDCBLOK
     DESCRIPTION: VIRTUAL/REAL DEVICE CHARACTERISTICS BLOCK
     DSECT      : VRDCBLOK
     FUNCTION   : THE VRDCBLOK CONTAINS 80 BYTES OF VIRTUAL AND
                  REAL DEVICE INFORMATION, AS WELL AS VIRTUALIZED
                  READ DEVICE CHARACTERISTICS DATA.
     LOCATED BY : USAGE DEPENDENT
     CREATED BY : HCPDVTDC
     DELETED BY : USAGE DEPENDENT
     COMMENTS   : ANY CHANGES TO THE FORMAT OF HARDWARE READ
                  DEVICE CHARACTERISTICS DATA SHOULD BE REFLECTED
                  TO THIS CONTROL BLOCK

#### VRDCBLOK Control Block Content

#### VRDCBLOK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      VRDCBLOK       VIRTUAL/REAL DEVICE
                                            CHARACTERISTICS BLOCK
    0000    0 Bitstring    2 VRDCDVNO       VIRTUAL DEVICE ADDRESS
    0002    2 Bitstring    2 VRDCLEN        VRDCBLOK LENGTH
    0004    4 Bitstring    4 VRDCVDAT (0)   VIRTUAL DEVICE DATA
    0004    4 Bitstring    2 VRDCVCOD (0)   VIRTUAL DEVICE CODE
    0004    4 Bitstring    1 VRDCVCLA       R*1 VIRTUAL DEVICE CLASS
    0005    5 Bitstring    1 VRDCVTYP       R*2 VIRTUAL DEVICE TYPE
    0006    6 Bitstring    1 VRDCVSTA       R*3 VIRTUAL DEVICE STATUS
    0007    7 Bitstring    1 VRDCVFLA       R*4 VIRTUAL DEVICE FLAG
    0008    8 Bitstring    4 VRDCRCDT (0)   REAL DEVICE DATA
    0008    8 Bitstring    2 VRDCRCCO (0)   REAL DEVICE CODE
    0008    8 Bitstring    1 VRDCRCCL       R*5 REAL DEVICE CLASS
    0009    9 Bitstring    1 VRDCCRTY       R*6 REAL DEVICE TYPE
    000A   10 Bitstring    1 VRDCCRMD       R*7 REAL DEVICE MODEL
    000B   11 Bitstring    1 VRDCRLLE (0)   REAL DEVICE LINE LENGTH
    000B   11 Bitstring    1 VRDCCRFT       R*8 REAL DEVICE FEATURE
    000C   12 Bitstring    1 VRDCUNDV       UNDERLYING DEVICE CODE FOR
                                            DEVICES THAT EMULATE OTHER DEVICE
                                            TYPES. VALID ONLY FOR CLASTAPE
                                            DEVICES. ZERO FOR ALL OTHER
                                            DEVICE CLASSES. VRDCUNDV Values
                                            for CLASTAPE devices
              .... ....      VRDCTNAT       X'00' Native non-emulation drive
              .... ...1      VRDCT120       X'01' 3590 128-TRK drive (B1A or
                                            B11) attached to 3590 A00/A50/A60
                                            control unit, emulating 3490E
              .... ..1.      VRDCTVTS       X'02' 3490E virtual drive in a
                                            3494 VTS tape library
              .... ..11      VRDCT121       X'03' 3590 128-TRK drive (B1A or
                                            B11) attached to 3591 control
                                            unit, emulating 3490E
              .... 1..1      VRDCT255       X'09' 3590 256-TRK drive (E1A or
                                            E11) attached to 3590 A00/A50/A60
                                            control unit, emulating 3590 B1A
                                            or B11
              .... 1.1.      VRDCT254       X'0A' 3590 256-TRK drive (E1A or
                                            E11) attached to 3590 A00/A50/A60
                                            control unit, emulating 3490E
              .... 1.11      VRDCT384       X'0B' 3590 384-TRK drive (H11 or
                                            H1A) attached to 3590 A60 control
                                            unit, emulating 3590/B1x
              .... 11..      VRDCT383       X'0C' 3590 384-TRK drive (H11 or
                                            H1A) attached to 3590 A60 control
                                            unit, emulating 3490E
              1111 1111      VRDCTUNK       X'FF' Unknown emulation drive
    000D   13 Bitstring    3 VRDCRSVD       RESERVED: MUST BE ZEROES
         CKD/ECKD dasd Read Device Characteristics (RDC) mapping (most other
         devices are similarly mapped)
    0010   16 Bitstring   64 VRDCSTRT (0)   START OF THE RDC DATA BYTES
    0010   16 Bitstring    2 VRDCCUTY       CONTROL UNIT TYPE
    0012   18 Bitstring    1 VRDCCUMD       R*9 CONTROL UNIT MODEL
    0013   19 Bitstring    2 VRDCDVTY       DEVICE TYPE
    0015   21 Bitstring    1 VRDCDVMD       R*10 DEVICE MODEL
    0016   22 Bitstring    4 VRDFEAT (0)    DEVICE / STORAGE DIR. FEATURES
    0016   22 Bitstring    3 VRDCDVFE       RESERVED FOR FUTURE IBM USE
    0019   25 Bitstring    1 VRDCSDFE       R*11 SUBSYTEM FEATURES SUPPORTED
    001A   26 Bitstring    1 VRDCDVCL       R*12 DEVICE CLASS CODE
    001B   27 Bitstring    1 VRDCDVCO       R*13 DEVICE TYPE CODE
    001C   28 Bitstring   28 VRDDEVF1 (0)   DEVICE SPECIFIC FIELD 1
    001C   28 Signed       2 VRDCPRIM       NUMBER OF PRIMARY CYLINDERS
    001E   30 Signed       2 VRDCTRKC       TRACKS PER CYLINDER
    0020   32 Bitstring    1 VRDCSECT       R*14 NUMBER OF SECTORS
    0021   33 Bitstring    3 VRDCTOTR       TOTAL USABLE TRACK LINGTH
    0024   36 Bitstring    2 VRDCHA         LENGTH FOR HA AND R0
    0026   38 Bitstring    1 VRDCMODE       R*16 TRACK-CAPACITY CALCULATION
                                            MODE
    0027   39 Bitstring    5 VRDMDFR (0)    TRACK-CAP CALCULATION FACTORS
    0027   39 Bitstring    1 VRDCMDFR       R*17 TRACK CAPACITY CALCULATION
                                            CHGNED
    0028   40 Signed       2 VRDCNKOV       NON-KEYED RECORD OVERHEAD
    002A   42 Signed       2 VRDCKOVH       KEYED AREA OVERHEAD
    002C   44 Signed       2 VRDCALTC       ADDRESS OF FIRST ALTERNATE CYL
    002E   46 Signed       2 VRDCALTR       NUMBER OF ALTERNAME TRACKS
    0030   48 Signed       2 VRDCDIG        ADDRESS OF DIAGNOSTIC CYLINDER
    0032   50 Signed       2 VRDCDIGN       NUMBER OF DIAGNOSTIC TRACKS
    0034   52 Signed       2 VRDCDVCY       ADDRESS OF FIRST DEVICE CYLINDER
    0036   54 Signed       2 VRDCDVTR       NUMBER OF DEVICE SUPPORT TRACKS
    0038   56 Bitstring    1 VRDCMDR        R*18 MDR RECORD ID
    0039   57 Bitstring    1 VRDCOBR        R*19 OBR RECORD ID
    003A   58 Bitstring   22 VRDDEVF2 (0)   DEVICE SPECIFIC FIELD 2
    003A   58 Bitstring    1 VRDCCUID       R*20 CONTROL UNIT ID
    003B   59 Bitstring    1 * (21)         RESERVED
    0050   80 Bitstring   11 VRDCPGID       Real Path Group ID
    005B   91 Bitstring    5 *              Reserved
              00000050       VRDCLNGC       *-VRDCSTRT SIZE OF VRDC DATA FOR
                                            CKD DEVICE
              0000000C       VRDCSIZE       (*-VRDCBLOK+7)/8 Size of VRDCBLOK
                                            in doublewords
         FBA dasd Read Device Characteristics (RDC) mapping
         *** BYTES DEFINED FOR FBA DEVICE IN VRDCSTRT
    0010   16 Bitstring   32 VRDCFBA (0)    ALL 32 RDC BYTES
    0010   16 Bitstring    1 VRDCOPER       DEVICE OPERATION MODES
    0011   17 Bitstring    1 VRDCFBAF       FBA DEVICE FEATURES
    0012   18 Bitstring    1 VRDCFBAC       FBA DEVICE CLASS
    0013   19 Bitstring    1 VRDCFBAT       FBA DEVICE TYPE
    0014   20 Bitstring   28 VRDFBAD1 (0)   -
    0014   20 Bitstring    2 VRDCRCSZ       PHYSICAL RECORD SIZE
    0016   22 Bitstring    4 VRDCBKCG       BLOCKS PER CYCLICAL GROUP (TRACK)
    001A   26 Bitstring    4 VRDCBKAP       BLOCKS PER ACCESS POSITION
    001E   30 Bitstring    4 VRDCBKMA       BLOCKS UNDER MOVABLE ACCESS
    0022   34 Bitstring    4 VRDCBKFA       BLOCKS UNDER FIXED ACCESS
    0026   38 Bitstring    2 VRDCBKAA       BLOCKS IN ALTERNATE AREA
    0028   40 Bitstring    2 VRDCBKCE       BLOCKS IN CE AREA
    002A   42 Bitstring    2 VRDCBFLG       NUMBER OF BUFFERED LOG BYTES
    002C   44 Bitstring    2 VRDCATMI       MINIMUM ACCESS TIME
    002E   46 Bitstring    2 VRDCATMA       MAXIMUM ACCESS TIME
    003A   58 Bitstring   22 VRDFBAD2       -
    0050   80 Bitstring   16 *              Reserved
         Tape Read Device Characteristics (RDC) mapping
         *** BYTES DEFINED FOR TAPE IN VRDDEVF1
    001C   28 Bitstring   28 VRDTAPE1       TAPE SPECIFIC RESERVED
         *** BYTES DEFINED FOR TAPE IN VRDDEVF2
    003A   58 Bitstring   22 VRDTAPE2       TAPE SPECIFIC RESERVED
    0050   80 Bitstring   16 *              Reserved

#### VRDCBLOK Storage Layout

    *** VRDCBLOK - VIRTUAL/REAL DEVICE CHARACTERISTICS BLOCK
    *
    *     +-------------+-------------+------+------+------+------+
    *   0 |  VRDCDVNO   |  VRDCLEN    |:CVCLA|:CVTYP|:CVSTA|:CVFLA|
    *     +------+------+------+------+------+------+------+------+
    *   8 |:CRCCL|:CCRTY|:CCRMD|:CCRFT|:CUNDV|     VRDCRSVD       |
    *     +------+------+------+------+------+------+-------------+
    *  10 |  VRDCCUTY   |:CCUMD|  VRDCDVTY   |:CDVMD| VRDCDVFE-   |
    *     +------+------+------+------+------+------+-------------+
    *  18 |-(016)|:CSDFE|:CDVCL|:CDVCO|  VRDCPRIM   |  VRDCTRKC   |
    *     +------+------+------+------+-------------+------+------+
    *  20 |:CSECT|     VRDCTOTR       |   VRDCHA    |:CMODE|:CMDFR|
    *     +------+------+-------------+-------------+------+------+
    *  28 |  VRDCNKOV   |  VRDCKOVH   |  VRDCALTC   |  VRDCALTR   |
    *     +-------------+-------------+-------------+-------------+
    *  30 |  VRDCDIG    |  VRDCDIGN   |  VRDCDVCY   |  VRDCDVTR   |
    *     +------+------+------+------+-------------+-------------+
    *  38 |:CMDR |:COBR |:CCUID|//////////////////////////////////|
    *     +------+------+------+//////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *  50 |                       VRDCPGID                        |
    *     |                    +----------------------------------+
    *  58 |                    |//////////////////////////////////|
    *     +--------------------+----------------------------------+
    *  60
    *
    *** VRDCBLOK - VIRTUAL/REAL DEVICE CHARACTERISTICS BLOCK

    *** Overlay for VRDCSTRT in VRDCBLOK
    *
    *     +------+------+------+------+-------------+-------------+
    *  10 |:COPER|:CFBAF|:CFBAC|:CFBAT|  VRDCRCSZ   | VRDCBKCG-   |
    *     +------+------+------+------+-------------+-------------+
    *  18 |   -(016)    |         VRDCBKAP          | VRDCBKMA-   |
    *     +-------------+---------------------------+-------------+
    *  20 |   -(01E)    |         VRDCBKFA          |  VRDCBKAA   |
    *     +-------------+-------------+-------------+-------------+
    *  28 |  VRDCBKCE   |  VRDCBFLG   |  VRDCATMI   |  VRDCATMA   |
    *     +-------------+-------------+-------------+-------------+
    *  30
    *
    *** Overlay for VRDCSTRT in VRDCBLOK

    *** Overlay for VRDDEVF2 in VRDCBLOK
    *
    *                   +-----------------------------------------+
    *  38 ...        3A |                                         |
    *     +-------------+                                         |
    *     |                       VRDFBAD2                        |
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  50 |///////////////////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *  60
    *
    *** Overlay for VRDDEVF2 in VRDCBLOK

    *** Overlay for VRDDEVF1 in VRDCBLOK
    *
    *                                 +---------------------------+
    *     ...                      1C |                           |
    *     +---------------------------+                           |
    *  20 |                                                       |
    *     =                       VRDTAPE1                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  38
    *
    *** Overlay for VRDDEVF1 in VRDCBLOK

    *** Overlay for VRDDEVF2 in VRDCBLOK
    *
    *                   +-----------------------------------------+
    *  38 ...        3A |                                         |
    *     +-------------+                                         |
    *     |                       VRDTAPE2                        |
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  50 |///////////////////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *  60
    *
    *** Overlay for VRDDEVF2 in VRDCBLOK

#### VRDCBLOK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    VRDCALTC       002C
    VRDCALTR       002E
    VRDCATMA       002E
    VRDCATMI       002C
    VRDCBFLG       002A
    VRDCBKAA       0026
    VRDCBKAP       001A
    VRDCBKCE       0028
    VRDCBKCG       0016
    VRDCBKFA       0022
    VRDCBKMA       001E
    VRDCCRFT       000B
    VRDCCRMD       000A
    VRDCCRTY       0009
    VRDCCUID       003A
    VRDCCUMD       0012
    VRDCCUTY       0010
    VRDCDIG        0030
    VRDCDIGN       0032
    VRDCDVCL       001A
    VRDCDVCO       001B
    VRDCDVCY       0034
    VRDCDVFE       0016
    VRDCDVMD       0015
    VRDCDVNO       0000
    VRDCDVTR       0036
    VRDCDVTY       0013
    VRDCFBA        0010
    VRDCFBAC       0012
    VRDCFBAF       0011
    VRDCFBAT       0013
    VRDCHA         0024
    VRDCKOVH       002A
    VRDCLEN        0002
    VRDCLNGC       005B 00000050
    VRDCMDFR       0027
    VRDCMDR        0038
    VRDCMODE       0026
    VRDCNKOV       0028
    VRDCOBR        0039
    VRDCOPER       0010
    VRDCPGID       0050
    VRDCPRIM       001C
    VRDCRCCL       0008
    VRDCRCCO       0008
    VRDCRCDT       0008
    VRDCRCSZ       0014
    VRDCRLLE       000B
    VRDCRSVD       000D
    VRDCSDFE       0019
    VRDCSECT       0020
    VRDCSIZE       005B 0000000C
    VRDCSTRT       0010
    VRDCTNAT       000C 00
    VRDCTOTR       0021
    VRDCTRKC       001E
    VRDCTUNK       000C FF
    VRDCTVTS       000C 02
    VRDCT120       000C 01
    VRDCT121       000C 03
    VRDCT254       000C 0A
    VRDCT255       000C 09
    VRDCT383       000C 0C
    VRDCT384       000C 0B
    VRDCUNDV       000C
    VRDCVCLA       0004
    VRDCVCOD       0004
    VRDCVDAT       0004
    VRDCVFLA       0007
    VRDCVSTA       0006
    VRDCVTYP       0005
    VRDDEVF1       001C
    VRDDEVF2       003A
    VRDFBAD1       0014
    VRDFBAD2       003A
    VRDFEAT        0016
    VRDMDFR        0027
    VRDTAPE1       001C
    VRDTAPE2       003A

This information is based on z/VM V4R3.0. Last updated on 30 Apr 2002 at 18:38:34 EDT.
Copyright IBM Corporation, 1990, 2002