TFDS Manual

Fast Memory Dump
Tandem Failure Data System (TFDS) Manual—520628-003
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Fast Memory Dumping Commands
TFDS is designed to process software halts. After that determination is made, TFDS
starts a dialog with Garth to extract incident data from the halted processor. Using this
data, TFDS determines if this incident is a duplicate of an earlier incident or a new
incident. If TFDS deems this incident to be a root incident, the initial dump process is
activated.
Initial Dump
When a processor halts, TFDS dumps only a subset of physical memory. The amount
of memory dumped is sufficient to allow the processor to be reloaded with only that
much memory available. If AUTORELOAD is disabled, the initial dump is directed to
dump all memory.
Processor Reload with Partial Memory Availability
After completion of the initial dump, TFDS begins a processor reload (if
AUTORELOAD is enabled). The reloaded processor is allowed to use only the amount
of memory that was dumped in the initial dump stage. Memory management keeps the
remainder of the memory off limits so that it can be dumped in the post-reload dump
stage.
Post Reload Dump
After a successful reload, a post-reload dump is run in the processor just reloaded and
dumps the remaining memory (not dumped in the initial dump), releasing it for general
use as it is dumped.
Fixup Utility
Two partial dump files are generated by the previous stages. These files are linked
when TFDS activates the fixup utility. This utility puts links within each dump file that
point to the other dump file.
Fast Memory Dumping Commands
Five commands relate to and control the Fast Memory Dump processing:
Command Description
FMDUMP Activates the FMD process within TFDS. Automatically set but can
be overridden by setting it to OFF in the TFDS configuration file.
FMDINITCPU Indicates the processor that is used to run the first partial dump of a
halted processor. The default is set to the buddy processor.
FMDINITPRIORITY Indicates the process priority at which the initial dump process will
execute.
FMDPOSTPRIORITY Allows selecting the process priority at which the post-reload dump
process executes.
FMDSIZE Sets the size of the first partial dump of a halted processor that is
generated by the initial dump process.