LCDA Back to Index page
 
Prolog 
Control Block Contents 
   LCDA DSECT
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.


  LCDA Prolog Top of page
 
 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 HCPFMU/HCPFMP.
 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 HCPFMU/HCPFMP.
 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
 RELOCATION CONSIDERATIONS : None
 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 Top of page
 

 LCDA DSECT Top of page
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' LCDZEROS 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 Top of page
 
          
*** LCDA - Locate data area
*
*     +------+------+-------------+---------------------------+
*   0 |LCDOP |:RPCNT|  LCDBKCNT   |         LCDBLOK           |
*     +------+------+-------------+---------------------------+
*   8
*
*** LCDA - Locate data area
 
 
  LCDA Cross Reference Top of page
 
 
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
 
This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:28:48 EDT.
Copyright IBM Corporation, 1990, 2020