BIOPG Back to Index page
 
Prolog 
Control Block Contents 
   BIOPG 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.


  BIOPG Prolog Top of page
 
 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
 RELOCATION CONSIDERATIONS : None
 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 Top of page
 

 BIOPG DSECT Top of page
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 Top of page
 
          
*** 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 Top of page
 
 
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 7.3.0 Last updated on 22 Jun 2022 at 15:47:37 EDT.
Copyright IBM Corporation, 1990, 2022