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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. |
VEXBK
Cross Reference (Contains links to field and bit definitions)
VEXBK Prolog
NAME : HCPVEXBK
DESCRIPTION: Volume EXtent block
DSECT : VEXBK
FUNCTION : Contains information about all of the extents on a
CP-owned volume.
LOCATED BY : CPVVEXBK
CREATED BY : HCPRDAAT when CP-owned volume attached
to system
DELETED BY : HCPRDDDT when CP-owned volume detached
from system
REFERENCES : HCPEXTBK - Extent block
SERIALIZED : Allocation locks
Notes : The fields starting at VEXPGACA and VEXSPACA each cannot
cross a 256-byte boundary because the internal CASBK
pointers (CASNXT) are one-byte fields. To guarantee
these fields do not cross a 256 byte-boundary,
ALLOC=ALIGNED is specified in IDOFFSET macro AND
currently the block has a maximum length of 256 bytes.
The length of 256 bytes PLUS ALLOC=ALIGNED forces the
control block to be located on a 256-byte boundary.
If this control block grows larger than 256 bytes,
then VEXSIZE as well as the locations of VEXPGACA and
VEXSPACA may need to change.
VEXBK Control Block Content
VEXBK DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure VEXBK Volume EXtent block The following section of the VEXBK contains information regarding the PAGE space on this volume. This information is for page slot allocation. This is the area containing page CASBKs (groups of Contiguous Available Slots) and is mapped by ACABK DSECT (Area for Contiguous Available Slots). 0000 0 Dbl-Word 8 * (0) 0000 0 Signed 4 VEXPGACA (16) Contains 16 CASBKs used by slot allocation. 0040 64 Signed 4 * Current slot number in EXTBK (start search for new CASBK here) 0044 68 Signed 4 * Last slot in current cylinder 0048 72 Signed 4 * Current cylinder in EXTBK 004C 76 Signed 4 * Pointer to current EXTBK 0050 80 Bitstring 1 * Index into ACABK of first CASBK 0051 81 Bitstring 1 * Index into ACABK of last CASBK 0052 82 Bitstring 1 * Flags 0053 83 Bitstring 1 * (5) Reserved for IBM use The following section of the VEXBK contains information regarding the SPOOL space on this volume. This information is for spool slot allocation. This is the area containing page CASBKs (groups of Contiguous Available Slots) and is mapped by ACABK DSECT (Area for Contiguous Available Slots). 0058 88 Dbl-Word 8 * (0) 0058 88 Signed 4 VEXSPACA (16) Contains 16 CASBKs used by slot allocation. 0098 152 Signed 4 * Current slot number in EXTBK (start search for new CASBK here) 009C 156 Signed 4 * Last slot in current cylinder 00A0 160 Signed 4 * Current cylinder in EXTBK 00A4 164 Signed 4 * Pointer to current EXTBK 00A8 168 Bitstring 1 * Index into ACABK of first CASBK 00A9 169 Bitstring 1 * Index into ACABK of last CASBK 00AA 170 Bitstring 1 * Flags 00AB 171 Bitstring 1 * (5) Reserved for IBM use The following section of the VEXBK is a general section containing pointers to the first EXTBK of each type and the number of EXTBKs of each type, as well as descriptions about the device geometry. If one of the following pointers is 0, then no space of that type exists on the volume. 00B0 176 Signed 4 VEXPGEXT Ptr to 1st page EXTBK on volume 00000004 VEXPTRL *-VEXPGEXT Length of each pointer field 00B4 180 Signed 4 VEXSPEXT Ptr to 1st spool EXTBK on volume 00B8 184 Signed 4 VEXTDEXT Ptr to 1st tdsk EXTBK on volume 00BC 188 Signed 4 VEXDREXT Ptr to 1st drct EXTBK on volume 00C0 192 Signed 4 VEXPEEXT Ptr to 1st perm EXTBK on volume 00000014 VEXPTRT *-VEXPGEXT Total area for pointers 00000005 VEXTYP VEXPTRT/VEXPTRL Number of allocation types with EXTBKs 00C4 196 Signed 4 VEX1SEXT Pointer to 1st EXTBK of any type 00C8 200 Signed 2 VEXPGNUM Number page EXTBKs on volume 00000002 VEXCTRL *-VEXPGNUM Length of each counter field 00CA 202 Signed 2 VEXSPNUM Number spool EXTBKs on volume 00CC 204 Signed 2 VEXTDNUM Number tdsk EXTBKs on volume 00CE 206 Signed 2 VEXDRNUM Number drct EXTBKs on volume 00D0 208 Signed 2 VEXPENUM Number perm EXTBKs on volume 00D2 210 Signed 2 VEXNUMEX Total number EXTBKs on volume 00D4 212 Bitstring 1 VEXTYPES Indicates all allocation types that exist on the volume. PARM and UNDF types are marked separately in VEXFLAGS. 00D5 213 Bitstring 1 VEXAVAIL Indicates which types have available space on the volume. PARM and UNDF types are marked separately in VEXFLAGS. 00D6 214 Signed 2 VEXPGCYL Pages per cylinder (Valid only for CKD devices) 00D8 216 Bitstring 1 VEXVOL Volume index (v of ccpv) 00D9 217 Bitstring 1 VEXFLAGS Flag byte 1... .... VEXFBA X'80' FBA indicator .1.. .... VEXNFIL X'40' Device formatted without filler records ..1. .... VEXUNDF X'20' Device contains undefined allocation types. Those areas will be ignored. ...1 .... VEXPARM X'10' Device contains cyls/pages with PARM allocation type 00DA 218 Bitstring 1 * (2) Reserved for IBM use 00DC 220 Signed 4 VEXEND Number of cylinders (CKD) or slots (FBA) on device 00E0 224 Signed 4 VEXMXCYL Maximum number of cylinders per page/spool EXTBK (Used only for CKD device) 00000020 VEXSIZE 256/8 Current maximum size of VEXBK in Dwords. This forces VEXBK to be aligned on a 256-byte boundary.
VEXBK Storage Layout
*** VEXBK - Volume EXtent block * * +-------------------------------------------------------+ * 0 | | * = VEXPGACA = * | | * +---------------------------+---------------------------+ * 40 |///////////////////////////|///////////////////////////| * +---------------------------+---------------------------+ * 48 |///////////////////////////|///////////////////////////| * +------+------+------+------+---------------------------+ * 50 |//////|//////|//////|//////////////////////////////////| * +------+------+------+----------------------------------+ * 58 | | * = VEXSPACA = * | | * +---------------------------+---------------------------+ * 98 |///////////////////////////|///////////////////////////| * +---------------------------+---------------------------+ * A0 |///////////////////////////|///////////////////////////| * +------+------+------+------+---------------------------+ * A8 |//////|//////|//////|//////////////////////////////////| * +------+------+------+------+---------------------------+ * B0 | VEXPGEXT | VEXSPEXT | * +---------------------------+---------------------------+ * B8 | VEXTDEXT | VEXDREXT | * +---------------------------+---------------------------+ * C0 | VEXPEEXT | VEX1SEXT | * +-------------+-------------+-------------+-------------+ * C8 | VEXPGNUM | VEXSPNUM | VEXTDNUM | VEXDRNUM | * +-------------+-------------+------+------+-------------+ * D0 | VEXPENUM | VEXNUMEX |:TYPES|:AVAIL| VEXPGCYL | * +------+------+-------------+------+------+-------------+ * D8 |VEXVOL|:FLAGS|/////////////| VEXEND | * +------+------+-------------+---------------------------+ * E0 | VEXMXCYL | E4 * +---------------------------+ * *** VEXBK - Volume EXtent block
VEXBK Cross Reference
(contains links to field and bit definitions)Symbol Dspl Value -------------- ---- -----VEXAVAIL 00D5
VEXCTRL 00C8 00000002
VEXDREXT 00BC
VEXDRNUM 00CE
VEXEND 00DC
VEXFBA 00D9 80
VEXFLAGS 00D9
VEXMXCYL 00E0
VEXNFIL 00D9 40
VEXNUMEX 00D2
VEXPARM 00D9 10
VEXPEEXT 00C0
VEXPENUM 00D0
VEXPGACA 0000
VEXPGCYL 00D6
VEXPGEXT 00B0
VEXPGNUM 00C8
VEXPTRL 00B0 00000004
VEXPTRT 00C0 00000014
VEXSIZE 00E0 00000020
VEXSPACA 0058
VEXSPEXT 00B4
VEXSPNUM 00CA
VEXTDEXT 00B8
VEXTDNUM 00CC
VEXTYP 00C0 00000005
VEXTYPES 00D4
VEXUNDF 00D9 20
VEXVOL 00D8
VEX1SEXT 00C4
Last updated on 3 Aug 1999 at 13:44:54 EDT.
Copyright IBM Corporation, 1990, 1999