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
          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
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 V4R2.0. Last updated on 17 Oct 2001 at 17:22:01 EDT.
Copyright IBM Corporation, 1990, 2001