trace table entry, the identification code, identifies the type of event
being recorded. Figure 8 describes the format of each type of trace
table entry. Some trace table entries are generated by ECPS:VM. The first bit of these entries is set to 1 to indicate the entry was generated by the
hardware assist. For example, a trace table entry of type X'86' (FREE)
is the same as an entry of type X'06'. The only difference is that the
first entry was generated by the hardware assist.
The trace table is allocated by the main initialization routine, D8KCPI. The first event traced is placed in the lowest trace table
address. Each subsequent event is recorded 1n the next available trace
table entry. Once the trace table is full, events are recorded at the
lowest address (overlaying the data previously recorded there). Tracing
continues with each new entry replacing an entry from a previous cycle. Use the trace table to determine the events that preceded a CP systea failure. An abend dump contains the CP internal trace table and the
Fointers to it. The address of the start of the. trace table, TRACSTRT, is at location X'OC'. The address of the byte the end of the
trace table, TRACEND, is at location X'10'. And the address of the next
available trace table entry, TRACCURR, is at lecation X'14'. Subtract
16 bytes (X'10') from the address stored at X'14' (TRACCUBR) to obtain
the trace table entry for the last event completed.
The CP internal trace table is initialized during IPL. If you do not
wish to record events in the trace table, issue the MONITOR STOP command to suppress recording. The pages allocated to the trace table are not
released and recording can be restarted at any time by issuing the MONITOR START command. If the V8/370 system should abnormally terminate
and automatically restart, the tracing of events on the real machine
will be active. After a V8/370 IPL (manual or automatic), CP internal
tracing is always active. Part 1. Debugging vith 15/370 43

page of GC20-1807-7 As Updated April 1, 1981 by TNL GN25-0829 your viLtual machine cannot continue, it terminates and, in some cases,
attempts to issue a dump. In the VM/370 environment, the problem proq-r-am-dum-palwa-ys- goes - t-othe- v-irtllal- _printer. De-ItendiJ)_q installation operating procedures, the virtual machine operating system
dump may also go to the virtual printer. A CLOSE must be issued to the
virtual printer to have either dump print on the real printer.
The third type of dump occurs when the CP system cannot continue.
The CP abnormal termination dumps can be directed to a printer or tape
or be dynamically allocated to DASD. If the dump is directed to a tape,
the dumped data must fit on one reel of tape. Multiple tape volumes are
not supported by VM/370. The historical data on the tape is in print
line format and can be processed by user-created programs or via CMS commands. specify the output device for CP abend dumps with the CP SET command. When the CP abend dump is sent to a disk, use the CMS VMFDUMP command
to print the dump on the real printer. Use the VMFDUMP command to format and print a current or previous VM/370 system abend dump. Specify VMFDUMP to obtain a complete formatted, hexadecimal printout. When the dump has been printed, one of two messages will be printed. DUMP FILE - DUMP xx - PRINTED AND KEPT
-- or -- DUMP FILE - DUMP xx -PRINTED AND ERASED. HOW TO PRINT A CP ABEND DUMP FROM TAPE When the CP abend dump is sent to a tape, the records are 131 characters
long, unblocked, and contain carriage control characters.
To pLint the tape, first make sure the tape drive is attached to your
system. Next, define the printer and tape file.
FILEDEF ddname1 PRINTER (RECFM FM LRECL 131)
FILEDEF ddname2 {TAP2} (DEN 1600 RECFM U LRECL 132) TAP1 Then use the MOVEFILE command to print the tape: MOVEFILE ddname2 ddname1
An extended form of the VMFDUMP command may be used via the facilit.les cit IPCS (In-teracti-v-e-- Problem Cont.rolSystem)- by- Field
EnqineeLing Program Systems Representatives, and by installation system
programmers. For information on IPCS, refer to the publication !K/31g­ (lgcS) Part 1. Debugging with VM/370 45