BELBK | Back to Index page

| Prolog Control Block Contents BELBK 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.

BELBK Prolog | Top of page

     NAME       : HCPBELBK
     DESCRIPTION: Block I/O entry list
     DSECT      : BELBK
     FUNCTION   : This DSECT maps the input parameter list sent
                  by the guest to CP when the guest requests
                  an I/O operation via DIAGNOSE X'250'.
     LOCATED BY : BRQBELBK in the BRQBK
     CREATED BY : HCPBIDRW (who copies the guest's parameter
                  list into host storage)
     DELETED BY : HCPBIDRW, for synchronous requests
                  HCPBIDRW. for asynchronous requests
                  satisfied synchronously
                  HCPBIRIN, for asynchronous requests
                  satisfied asynchronously
     SERIALIZED : Instruction stream serialization
     RELOCATION CONSIDERATIONS : None
     COMMENTS   :
                  This parameter list may not be word-aligned in
                  guest storage. However, this DSECT assumes that
                  before any fields are referenced, the parameter
                  list has been moved into host storage and
                  word-aligned. References to fields in this block
                  will cause an exception if this is not the case.
                  There is one entry within the block I/O entry list
                  for each read/write request.
                  This control block is a GPI, and should
                  not be changed incompatibly.

BELBK Control Block Content | Top of page

     BELBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      BELBK          Block I/O entry list
    0000    0 Signed       4 * (0)
    0000    0 Bitstring    1 BELRQTYP       Type of operation being
                                            requested.
              00000001       BELWRITE       X'01' BELWRITE Write operation
                                            requested
              00000002       BELREAD        X'02' BELREAD Read operation
                                            requested
    0001    1 Bitstring    1 BELSTAT        Status code for this operation
              00000000       BELOK          X'00' BELOK The read or write
                                            operation was successful
              00000001       BELINVBK       X'01' BELINVBK Invalid block
                                            number specified
              00000002       BELADDRE       X'02' BELADDRE Addressing
                                            exception condition
              00000003       BELRODEV       X'03' BELRODEV A write operation
                                            was requested to a read-only
                                            device
              00000004       BELINVSZ       X'04' BELINVSZ Block size does
                                            not match that of the virtual
                                            device
              00000005       BELIOERR       X'05' BELIOERR Unrecoverable I/O
                                            error
              00000006       BELBADRQ       X'06' BELBADRQ Request type is
                                            not read or write
              00000007       BELPROTE       X'07' BELPROTE Protection
                                            exception condition
              00000008       BELADCPE       X'08' BELADCPE
                                            Addressing-capability exception
                                            condition
              00000009       BELALTRE       X'09' BELALTRE ALEN-translation
                                            exception condition
              0000000A       BELALSPE       X'0A' BELALSPE ALET-specification
                                            exception condition
              0000000B       BELSPECE       X'0B' BELSPECE Specification
                                            exception condition
              0000000C       BELNOTPR       X'0C' BELNOTPR This block I/O
                                            entry was not processed
    0002    2 Bitstring    2 BELRSD01       Reserved for IBM use
          Format of remainder of block when BIO64BIT = 0 in the BIOPL.
    0004    4 Signed       4 BELBKNUM       32 bit block number
    0008    8 Address      4 BELBALET       ALET of guest data buffer
    000C   12 Address      4 BELBUFAD       31 bit guest absolute address of
                                            the data buffer.
    0010   16 Signed       4 BELNEXT (0)    Start of next entry in p-list
              00000002       BELSIZE        (*-BELBK+7)/8 Size of one entry
                                            of the BELBK in doublewords
          Format of remainder of block when BIO64BIT = 1 in the BIOPL.
    0004    4 Address      4 BELBALETF1     ALET of guest data buffer
    0008    8 Dbl-Word     8 BELBKNUM64     64 bit block number
    0010   16 Address      8 BELBUFAD64     64 bit guest absolute address of
                                            the data buffer.
    0018   24 Signed       4 BELNEXTF1 (0)  Start of next entry in p-list
              00000003       BELSIZEF1      (*-BELBK+7)/8 Size of one entry
                                            of the BELBK in doublewords

BELBK Storage Layout | Top of page

    *** BELBK - Block I/O entry list
    *
    *     +------+------+-------------+---------------------------+
    *   0 |:RQTYP|:STAT |  BELRSD01   |         BELBKNUM          |
    *     +------+------+-------------+---------------------------+
    *   8 |         BELBALET          |         BELBUFAD          |
    *     +---------------------------+---------------------------+
    *
    *** BELBK - Block I/O entry list

    *** Overlay for BELBKNUM in BELBK
    *
    *                                 +---------------------------+
    *   0 ...                       4 |        BELBALETF1         |
    *     +---------------------------+---------------------------+
    *   8 |                      BELBKNUM64                       |
    *     +-------------------------------------------------------+
    *  10 |                      BELBUFAD64                       |
    *     +-------------------------------------------------------+
    *
    *** Overlay for BELBKNUM in BELBK

BELBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    BELADCPE       0001 00000008
    BELADDRE       0001 00000002
    BELALSPE       0001 0000000A
    BELALTRE       0001 00000009
    BELBADRQ       0001 00000006
    BELBALET       0008
    BELBALETF1     0004
    BELBKNUM       0004
    BELBKNUM64     0008
    BELBUFAD       000C
    BELBUFAD64     0010
    BELINVBK       0001 00000001
    BELINVSZ       0001 00000004
    BELIOERR       0001 00000005
    BELNEXT        0010
    BELNEXTF1      0018
    BELNOTPR       0001 0000000C
    BELOK          0001 00000000
    BELPROTE       0001 00000007
    BELREAD        0000 00000002
    BELRODEV       0001 00000003
    BELRQTYP       0000
    BELRSD01       0002
    BELSIZE        0010 00000002
    BELSIZEF1      0018 00000003
    BELSPECE       0001 0000000B
    BELSTAT        0001
    BELWRITE       0000 00000001

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:27:04 EDT.
Copyright IBM Corporation, 1990, 2020