Formatted dump for the DL/I address space

One of the tools available for problem diagnosis is the IMS formatted dump, which formats the control blocks and data areas in an IMS region. Dumped areas within the DL/I address space are listed and descriptive information has been added for some control blocks where it would be useful.

Dumped areas within the DL/I address space

System Contents Directory
The mapping DSECT is ISCD.
SCD Latch Extension
The mapping DSECT is ISCD.
Scheduler Sequence Queues
Controls the status of each region. The mapping DSECT is ISCD.
Save Area Trace
 
Save Area Prefix
All SAPs belonging to the DL/I address space are SNAPed. A SAP is marked ACTIVE if the ITASK associated with it is active. Each SAP is followed by its save area set. At the end of this section, all of the SAP IPAGES are dumped.
DLS Task Dispatch Work Areas
The mapping DSECT is IDSPWRK.
DBRC Task Dispatch Work Area
If present in the system, it is mapped.
Dependent Region Dispatch Work Area
For every dependent region in IMS, the dispatcher work area is mapped.
Dispatcher Trace Data
DSECT IDSPWRK contains the function codes associated with the dispatcher and an explanation of each code.
Latch Trace Data
The trace entries contain latch and unlatch function codes. The mapping DSECT is IDLIVSAM TRACENT.
System PSTs
These are system work areas for any online or batch region. The mapping DSECT is IPST.
PSB Directory
A SNAP of the PSB directory. The mapping DSECT is PDIR.
DMB Directory
A SNAP of the DMB directory. The mapping DSECT is DDIR.
Intent List
This is a SNAP of the intent list.
Partition Specification Table
Formats the PST. The mapping DSECT is IPST.
PDIR
Formats the PDIR, whose address is in the PST. The mapping DSECT for PDIR is PDIR.
PSB Prefix
A SNAP of the PSB prefix, which contains the following:
  • Index Maintenance Work Area
  • Index I/O Work Area
  • Segment Work Area
  • I/O Work Area
  • SSA Work Area
  • User PARMS Area
Buffer Handler Pool
The system attempts to format buffer handler blocks in the order in which they are chained on the queue. However, if an error is encountered during the formatting, the entire pool is dumped as is (unchained).
The pool contains the following:
BFSP
Formats the buffer pool prefix. The mapping DSECT is BFSP.
BFUS
Formats the subpool prefix. The mapping DSECT is BFUS.
RPLI
Formats the DL/I RPL block. The mapping DSECT is RPLI.
DL/I Data
A dump of the DL/I lock activity and program isolation trace table. The mapping DSECT is IDLIVSAM TRACENT.
Lock Activity Trace Data
See DL/I DATA.
Program Isolation Data
Includes the QEL, QCB, and REQ areas. The mapping DSECT is XC00.
OSAM Control Blocks
The system attempts to follow the main pool, the subpool header, and the buffer prefix, and to dump the buffer. However, if an error is encountered during formatting, the entire buffer pool is SNAPed from the last valid subpool address.
The pool contains the following:
MAINPOOL
Formats the main pool header. The mapping DSECT is IBPOOL.
SUBPOOL
Formats the subpool header. The mapping DSECT is ISUBPL.
Buffer Prefix
Formats the buffer prefix. The mapping DSECT is IBFPRF.
Buffer
Physical data not mapped.
OSAM I/O Control Blocks
The system attempts to dump the IOSB and IOMA control blocks. The mapping DSECT is QPOOL.
Sequential Buffering Blocks
Sequential Buffering information is grouped into the following three sections. (See the explanation of the (SB) FMTIMS option Solving IMS problems by using the IMS Offline Dump Formatter for a complete list of the blocks dumped in each section.)
  1. Subsystem Overview for Sequential Buffering
  2. PST Overview of Sequential Buffering control blocks
  3. Formatted Sequential Buffering control blocks
Fast Path DEDB Formatting
 
Fast Path EMH Formatting
 
Fast Path MDSB Formatting
 
IRLM Control Blocks
The IRLM Subsystem RLMCB block is formatted here if the IMS system is running with IRLM.
Format/Dump/Delete List
Contains module names, module IDs, and module dump data that are not in the storage dump listing.