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Programming Interface Information:
This information is NOT
intended to be
used as Programming Interfaces of VM/ESA. It is to be used for diagnosis only. |
BIOPG
Cross Reference (Contains links to field and bit definitions)
BIOPG Prolog
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
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
BIOPG DSECT
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
*** 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
(contains links to field and bit definitions)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
Last updated on 3 Aug 1999 at 11:41:57 EDT.
Copyright IBM Corporation, 1990, 1999