gtpn1m0e | Non-SNA Data Communications Reference |
Activating CCP Trace involves:
- Formatting the two 1055-byte low core trace areas in copy segment
CLVQ.
- Turning on a bit in the Lost Interrupt Table entry for the subchannel to
be traced. If trace is being activated for either the PRC or RO, then
the console trace bit for that subchannel is also turned on.
- Activating a hook at each point in the CCP that is to be
traced. These 'hooks' or intercepts cause the CCP to link to
the trace recording segment, CLVQ, instead of falling through the
hook and continuing normally.
Deactivating CCP trace involves:
- Turning off all non-console trace bits in the lost interrupt table.
If the console trace bit is on for a subchannel, neither bit is reset for that
subchannel.
- If necessary, writing the partially filled core block to tape.
- Indicating the non-console trace area in low core will need to be
reformatted before any non-console tracing is reactivated.
- Forcing trace into loop mode, so that in-core loop trace will continue on
the console devices.
As part of CCP Trace operation, all CCP Trace commands are written to the
RTL/RTA tape for DOF processing.
If CCP trace is active, whenever the CCP is processing CCP macros, SIOs,
HIOs or multiplexor interrupts, the operation is intercepted. Pertinent
information about the operation is recorded in the appropriate CCP trace low
core area (console or non-console), then the operation is allowed to
complete.
If the option to write the trace blocks to tape was selected, as each low
core trace area becomes full, a 1055-byte user storage block is
obtained. Also, the information is copied from the low core trace area
to the user storage block, and the user storage block is written to the
RTL/RTA tape. In addition, when CCP tape trace is deactivated, the last
two partially full trace areas are copied to user storage and written to the
RTL/RTA tape.
- CCP trace may not be running when VFA is stopped or reinitialized;
VFA will notify the operator to stop CCP trace before VFA processing is
allowed to continue.
- In a Loosely-Coupled environment, CCP trace can only be activated on a
non-EP processor by specifying the PRC or RO options. No other lines
may be traced on a non-EP processor.
- The PRC option is only valid if the PRC is currently on symbolic line
01.
- The RO option is only valid if the RO is currently on symbolic line 00 or
01.