Two special file names are used to analyze memory resident information as if it were a dump file on disk. These file names are LIVEDUMP and FASTDUMP.
When the TAPEIN file is file-equated to the reserved file name LIVEDUMP, DUMPANALYZER accesses current memory locations instead of a dump file.
When the TAPEIN file is file-equated to the reserved file name FASTDUMP, DUMPANALYZER attempts to load a dump taken using the MEMORYCEILING fast memory dump option. If a fast memory dump is resident in memory, the raw dump is analyzed by DUMPANALYZER directly from its reserved memory area.
The advantages of accessing a fast memory dump directly in memory are twofold. First, the dump can be viewed immediately upon completion without unloading. Second, DUMPANALYZER performance might be improved because access to the dump data is direct and does not require I/O. Note that if a fast memory dump does not exist in the reserved memory area, DUMPANALYZER attempts to open a disk file named FASTDUMP.
The following guidelines should be noted for the new options:
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When analyzing current memory using LIVEDUMP, memory words are obtained independently without any locking.
Because memory is volatile at the actual time of analysis, it is possible that DUMPANALYZER might report inconsistencies and potentially need to recover from fault situations when processing any particular command.
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For FASTDUMP, the fast memory dump area is not available for use for a new memory dump until the dump is cleared by DUMPDISKMASTER.
Depending on the MDT settings and the response to DUMPDISKMASTER, either a DP or SAVEDUMP file on disk or a memory dump tape can be created to preserve the fast memory dump.
Alternately, the fast dump can be marked as purged by responding to DUMPDISKMASTER with an AX PURGE response. The PURGE allows the dump to be overwritten by a subsequent memory dump request, but does not destroy the dump image in memory, allowing it to continue to be viewed by DUMPANALYZER.
Note that the AX SKIP response allows DUMPDISKMASTER to terminate, but does not release the memory area for use by another dump. DUMPDISKMASTER reappears to unload the dump following a halt/load or a DF (Empty Dump File) ODT request.
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DUMPANALYZER is unable to process a SAVE command directly from a fast dump in memory or while analyzing live memory.
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For security reasons, access to both the fast memory dump and current memory information through DUMPANALYZER is restricted to privileged users.
