Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM. |
LCDA
Control Block Contents
LCDA DSECT
Cross Reference (Contains links to field and bit definitions)
LCDA Prolog
Name : HCPLCDA Description: Locate data area DSECT : LCDA Function : Maps the contents of the Locate data area. Located by : HCCWADDR - The Locate CCW data address field contains the address of the locate data area. Created by : Storage for this control block cannot be specifically allocated/deallocated using HCPGETST/HCPRELST. Paging I/O manager - The data area resides in the HCPPIOBK which is allocated by HCPRDA. Track cache manager - Data area is part of a larger free storage area used to build FBA channel programs which is allocated in modules HCPFTU/HCPFTP. Deleted by : Storage for this control block cannot be specifically allocated/deallocated using HCPGETST/HCPRELST. Paging I/O manager - The data area resides in the HCPPIOBK which is allocated by HCPRDD. Track cache manager - Data area is part of a larger free storage area used to build FBA channel programs which is deallocated in modules HCPFTU/HCPFTP. Serialized : Paging I/O manager - EXPLCKFG - The paging I/O manager uses the exposure block lock to serialize this data area. Track cache manager - TCMTSLK - Track cache lock Comments : Paging I/O manager - The Locate data area resides in the HCPPIOBK. Each Locate CCW address field contains the address of the Locate data area within that PIOBK. Track cache manager - None
LCDA Control Block Content
LCDA DSECT
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure LCDA Locate data area 0000 0 Bitstring 8 LCDAREA (0) Locate data area Byte 0 (Operation byte) Although defined as BITs, the contents of the operation byte are, architecturally, multiple codes. 0000 0 Bitstring 1 LCDOP Operation byte .... .... LCDZEROS X'00' Operation byte, bits 0 - 3 .... 1111 LCDOOC X'0F' Operation byte, bits 4 through 7 ------- Codes for use with LCDOOC .... ...1 LCDOCWD X'01' Write data .... ..1. LCDOCRR X'02' Read Replicated Data .... .1.. LCDOCFD X'04' Format defective block .... .1.1 LCDOCWC X'05' Write and Check Data .... .11. LCDOCRD X'06' Read data ------- Byte 1 (Locate Replication Count) 0001 1 Bitstring 1 LCDRPCNT Replication count Bytes 2 and 3 (Block Count): Block count is the number of addressable blocks to be processed. 0002 2 Bitstring 2 LCDBKCNT Block count Bytes 4 through 7 (Block address): Block address is the addressable block number of the first block to be processed in the data space. 0004 4 Bitstring 4 LCDBLOK Block address Length equates 00000008 LCDBSIZE *-LCDAREA Size of LCDA in bytes 00000001 LCDSIZE ((*-LCDAREA)+7)/8 Size of LCDA in DWs
LCDA Storage Layout
*** LCDA - Locate data area * * +------+------+-------------+---------------------------+ * 0 |LCDOP |:RPCNT| LCDBKCNT | LCDBLOK | * +------+------+-------------+---------------------------+ * 8 * *** LCDA - Locate data area
LCDA Cross Reference
Symbol Dspl Value -------------- ---- ----- LCDAREA 0000 LCDBKCNT 0002 LCDBLOK 0004 LCDBSIZE 0004 00000008 LCDOCFD 0000 04 LCDOCRD 0000 06 LCDOCRR 0000 02 LCDOCWC 0000 05 LCDOCWD 0000 01 LCDOOC 0000 0F LCDOP 0000 LCDRPCNT 0001 LCDSIZE 0004 00000001 LCDZEROS 0000 00
Last updated on 5 Jun 2001 at 14:03:05 EDT.
Copyright IBM Corporation, 1990, 2001