Figure 112 shows the control blocks associated with the trace
domain.
- TR domain anchor block (TRA).
- There is one TRA in the system. It contains all status information
relating to the trace domain and also pointers to the other trace domain control
blocks.
- Internal trace table.
- An area of virtual storage above the 16MB line used for recording trace
entries.
- TR block (TRBL).
- The internal trace table consists of a number of TRBLs chained in a
loop. They are each 4096 bytes long. Each block contains a standard header
and a sequence of variable-length trace entries.
- Trace entry (TREN).
- All trace entries consist of a header together with any data specified
on the call. The length of each trace entry is in the range 32 through 4072
bytes.
- TR auxiliary trace data set DCB, DECB, and buffer.
- During the auxiliary trace start process, an MVS™ GETMAIN is issued to acquire storage below
the 16MB line for these areas. Their addresses are kept in the TRA. The storage
is released when auxiliary trace is stopped.
- GTF buffer.
- During the GTF trace start process, an MVS GETMAIN is issued to acquire
storage above the 16MB line for this area. It is 256 bytes long, and its
address is kept in the TRA. The storage is released when GTF trace is stopped.
The buffer is used when splitting large entries (more than 256 bytes) into
256-byte pieces to be written to GTF. This is done because GTF has a length
restriction of 256 bytes.
- Global trap/trace exit work area (TRGTW).
- When the FE global trap/trace exit (DFHTRAP) is activated, an MVS GETMAIN
is issued to acquire storage above the 16MB line for the TRGTW. This area
contains a register save area and all working storage associated with DFHTRAP,
including the parameter list passed to the exit program. Its address is kept
in the TRA. The storage is released when the trap is deactivated.
See the CICS® Data Areas manual for a detailed description of these control blocks.
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