PLATO Dump Files

– William Schaub and Steve Zoppi

The PLATO subsystem is a very old, thoroughly-tested codebase and seldom has issues during normal operation. Regardless, conditions arise in which the subsystem will terminate abnormally and when that happens, a “dump” procedure is initiated by the system to preserve the state of the system for a systems programmer's subsequent diagnosis.

The Retro1.Org team of systems programmers continues to maintain and enhance the codebase. While changes are rigorously tested, errors will appear. This article describes the procedure for preserving these diagnostic dump files for submission to the systems programmers for resolution.

If any of the PLATO subsystem components aborts, the crash dump processor will be initiated and messages to the NOS console will indicate the need to capture the diagnostic dump to virtual tape by displaying the message: wait for plato crash dumps to complete on the system's B display.

1. On DtCyber's Console, mount a tape on NOS Tape device 051 ¹⁾ using the command:

   lt 13,0,1,w,[path/to/tapefile]

2. On the NOS Console
   1. Type

      GO,JSN.

      where JSN is the Job Sequence Number of the job asking you to wait for the crash dumps.

   2. Type

      GO,JSN.

      again.

   3. Type

      ASSIGN,JSN,051.

The dump tape contains an image of Central Memory and Extended Memory. To extract a formatted printout of the Central Memory portion of the image:

1. On DtCyber's Console This is ONLY needed if your system isn't using the automated job separation feature of DtCyber.
   1. Remove paper from the printer using the command

      rp 12,5,[/path/to/report/output/file]

      The channel and equipment numbers 12,5 are those used by the NCC and Retro1.Org distributions.

2. On DtCyber's Console
   1. Load the dump tape created above using the command

      lt 13,0,1,r,[path/to/tapefile]

3. On the NOS Console
   1. type

      X.DUMPPRT(PLATO,TID=PLATEM)

      . Valid subsystem names (in the location highlighted as yellow text) are PLATO, CONDEN, MASTOR, FRAMAT, PNI

   2. Look for the message

      WAIT. MOUNT TAPE PLATEM

   3. Type

      GO,JSN.

      where JSN is the Job Sequence Number preceeding the wait message

   4. Wait for the BIO subsystem to become idle. (indicating that printing has stopped)

The EM dump will reflect the contents of Extended Memory system as it was at the time the last program aborted. This is only important when examining the EM space MASTOR occupies. Because MASTOR uses EM residing in a space just below the rest of the PLATO EM space. All other subsystem elements should share the same space in common with subsystem PLATO (PLA1).

1. On DtCyber's Console
   1. Load the dump tape created above using the command

      lt 13,0,1,r,[path/to/tapefile]

2. On the NOS Console
   1. type

      X.EMPRT(FWA,LWA,TID=PLATEM)

      . FWA (highlighted yellow) is the first word address and LWA is the last word address.

   2. Look for the message

      WAIT. MOUNT TAPE PLATEM

   3. Type

      GO,JSN.

      where JSN is the Job Sequence Number preceeding the wait message

   4. Wait for the BIO subsystem to become idle. (indicating that printing has stopped)

Once done printing everything, if your system is not configured for automatic job separation, remove the paper using the DtCyber Console Command

to remove the paper and place it in a file for examination.

An example dump of CONDEN is attached for your reference.