Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM. |
IDSBK
Control Block Contents
IDSBK DSECT
IDSEGENT DSECT
IDSLTENT DSECT
Cross Reference (Contains links to field and bit definitions)
IDSBK Prolog
NAME : HCPIDSBK DESCRIPTION: ISFC ID segment table DSECT : IDSBK FUNCTION : A simple segment-page table to locate address of a PTHBK or generate a unique ID for an ISFC resource. LOCATED BY : HCPBTB contains an anchor for each table. CREATED BY : HCPBTB as new entries are needed. DELETED BY : HCPBTB as old entries are discarded. SERIALIZED : The ISFC global lock (HCPBDSGL).
IDSBK Control Block Content
IDSBK DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure IDSBK ISFC ID segment table 0000 0 Signed 4 IDSCOUNT Total count of IDs in this table 0004 4 Signed 4 IDSHMARK High water mark for this table 0008 8 Dbl-Word 8 * Reserved The value of (IDSMAXSG*IDSEGBLN) for BLOCKMAP is 64*8 = 512 0010 16 Bitstring 16 IDSSTART Reserve IDSEGENT space 00000042 IDSSIZE (*-IDSBK+7)/8 Size of IDSBK in doublewords FUNCTION : This is the format for a single 'Segment Entry' in the IDSBK. LOCATED BY : IDSSTART contains IDSEGENT entries.
IDSEGENT DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure IDSEGENT ISFC ID segment table 0000 0 Signed 4 IDSEGCNT Count of IDs in this segment 0004 4 Address 4 IDSEGADD Address of segment page 00000008 IDSEGBLN *-IDSEGENT Length of segment entry in bytes FUNCTION : This is the format for a single 'Slot Entry' in the IDSBK. LOCATED BY : IDSSTART contains IDSLTENT entries.
IDSLTENT DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure IDSLTENT ISFC ID segment table 0000 0 Address 4 IDSLTADD Address of slot entry 0=>available 1=>allocated, not a pointer >1=>allocated, pointer to entry 00000004 IDSLTBLN *-IDSLTENT Length of slot entry in bytes IUCV is limited to 64K paths, so each of these tables can only have 64K entries. Each "slot" in a segment consists of a fullword, so each segment (4K page) can hold 1K slots. Therefore, the maximum number of segment entries per table is 64 and the maximum number of slots per segment is 1024. 00000040 IDSMAXSG 64 Maximum segment entries per table 00000400 IDSMAXSL 1024 Maximum slots per segment 00000001 IDSLTFUL 1 Zero implies slot available Non-zero implies slot allocated
IDSBK Storage Layout
*** IDSBK - ISFC ID segment table * * +---------------------------+---------------------------+ * 0 | IDSCOUNT | IDSHMARK | * +---------------------------+---------------------------+ * 8 |///////////////////////////////////////////////////////| * +-------------------------------------------------------+ * 10 | IDSSTART | * | | * +-------------------------------------------------------+ * 20 * *** IDSBK - ISFC ID segment table *** IDSEGENT - ISFC ID segment table * * +---------------------------+---------------------------+ * 0 | IDSEGCNT | IDSEGADD | * +---------------------------+---------------------------+ * 8 * *** IDSEGENT - ISFC ID segment table *** IDSLTENT - ISFC ID segment table * * +---------------------------+ * 0 | IDSLTADD | 4 * +---------------------------+ * *** IDSLTENT - ISFC ID segment table
IDSBK Cross Reference
Symbol Dspl Value -------------- ---- ----- IDSCOUNT 0000 IDSEGADD 0004 IDSEGBLN 0004 00000008 IDSEGCNT 0000 IDSHMARK 0004 IDSLTADD 0000 IDSLTBLN 0000 00000004 IDSLTFUL 0000 00000001 IDSMAXSG 0000 00000040 IDSMAXSL 0000 00000400 IDSSIZE 0010 00000042 IDSSTART 0010
This information is based on z/VM V4R1.0.
Last updated on 5 Jun 2001 at 13:55:19 EDT.
Copyright IBM Corporation, 1990, 2001