Programming Interface Information:
This information is NOT intended to be used as Programming Interfaces of z/VM. |
DRWBK
Control Block Contents
DRWBK DSECT
Cross Reference (Contains links to field and bit definitions)
DRWBK Prolog
NAME : HCPDRWBK DESCRIPTION: DASD Read/Write Channel Program Block DSECT : DRWBK FUNCTION : This DSECT maps the channel program created to process a *BLOCKIO or diagnose A4 I/O\request LOCATED BY : DVICHPRG field in HCPDVIOP CREATED BY : HCPDPSRW DELETED BY : HCPDPSCU SERIALIZED : Unique task execution VMDBK dispatch lock. The chain of DVIOPS is protected by the BLKIO lock, in HCPBLKIO
DRWBK Control Block Content
DRWBK DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure DRWBK DASD Read/Write Channel Program Block 0000 0 Dbl-Word 8 DRWCHPRG (0) Channel program segment 0000 0 Dbl-Word 8 DRWSEEK SEEK CCW 0008 8 Dbl-Word 8 DRWSSECT SET SECTOR CCW 0010 16 Dbl-Word 8 DRWSRCH SEARCH ID CCW 0018 24 Dbl-Word 8 DRWTIC1 TIC CCW 0020 32 Dbl-Word 8 DRWRDWR READ/WRITE CCW 0028 40 Dbl-Word 8 DRWTIC2 TIC CCW 00000030 DRWCHPSZ *-DRWCHPRG 0030 48 Bitstring 12 DRWDATA (0) Data area portion of channel program Segment 0030 48 Bitstring 6 DRWSKARG (0) SEEK argument (BBCCHH) 0030 48 Bitstring 2 DRWSKBIN SEEK: bin (BB) number 0032 50 Bitstring 2 DRWSKCYL SEEK: cylinder (CC) number 0034 52 Bitstring 2 DRWSKHED SEEK: head/track (HH) number 0036 54 Bitstring 5 DRWSRCAR (0) SEARCH ID equal argument (CCHHR) 0036 54 Bitstring 2 DRWSRCYL SEARCH: cylinder (CC) number 0038 56 Bitstring 3 DRWSRHHR (0) SEARCH: head + record (HHR) 0038 56 Bitstring 2 DRWSRHED SEARCH: head/track (HH) number 003A 58 Bitstring 1 DRWSRREC SEARCH: record (R) number 003B 59 Bitstring 1 DRWSECTR SET SECTOR: sector number 003C 60 Signed 4 * Reserved for IBM use 00000040 DRWBSIZE *-DRWCHPRG Byte size of channel program (CCWs plus data area) 00000008 DRWSIZE (DRWBSIZE+7)/8 Doubleword size of channel program (CCWs plus data area) 0040 64 Dbl-Word 8 DRWNXTSG (0) Start of next channel program segment
DRWBK Storage Layout
*** DRWBK - DASD Read/Write Channel Program Block * * +-------------------------------------------------------+ * 0 | DRWSEEK | * +-------------------------------------------------------+ * 8 | DRWSSECT | * +-------------------------------------------------------+ * 10 | DRWSRCH | * +-------------------------------------------------------+ * 18 | DRWTIC1 | * +-------------------------------------------------------+ * 20 | DRWRDWR | * +-------------------------------------------------------+ * 28 | DRWTIC2 | * +-------------+-------------+-------------+-------------+ * 30 | DRWSKBIN | DRWSKCYL | DRWSKHED | DRWSRCYL | * +-------------+------+------+-------------+-------------+ * 38 | DRWSRHED |:SRREC|:SECTR|///////////////////////////| * +-------------+------+------+---------------------------+ * *** DRWBK - DASD Read/Write Channel Program Block
DRWBK Cross Reference
Symbol Dspl Value -------------- ---- ----- DRWBSIZE 003C 00000040 DRWCHPRG 0000 DRWCHPSZ 0028 00000030 DRWDATA 0030 DRWNXTSG 0040 DRWRDWR 0020 DRWSECTR 003B DRWSEEK 0000 DRWSIZE 003C 00000008 DRWSKARG 0030 DRWSKBIN 0030 DRWSKCYL 0032 DRWSKHED 0034 DRWSRCAR 0036 DRWSRCH 0010 DRWSRCYL 0036 DRWSRHED 0038 DRWSRHHR 0038 DRWSRREC 003A DRWSSECT 0008 DRWTIC1 0018 DRWTIC2 0028
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