System Troubleshooting and Diagnostics
5.2 Product Fault Management and Symptom-Directed Diagnosis
Figure 5–7 Correctable Read Data (CRD) Entry
3 1
0 0
0 7
0 8
1 5
1 6
2 3
2 4
0.
4.
8.
12.
16.
24.
32.
36.
Footprint
Status
CRD CNT
Pages Marked Bad CNT
Lowest Address
Highest Address
First Event
Last Event
MLO-007269
Each Memory CRD Entry represents one unique DRAM within the memory
subsystem. A unique set, bank, and syndrome are stored in footprint to
construct a unique ID for the DRAM.
Rather than logging an error for each occurrence of a single symbol
correctable ECC memory error, the OpenVMS error handler maintains
the CRD buffer—it creates a Memory CRD Entry for new footprints and
updates an existing Memory CRD Entry for errors that occur within the
range specified by the ID in FOOTPRINT. This reduces the amount of data
logged overall without losing important information—errors are logged per
unique failure mode rather than on a per error basis.
Each Memory CRD entry consists of a FOOTPRINT, STATUS, CRD CNT,
PAGE MAPOUT CNT, FIRST EVENT, LAST EVENT, LOWEST ADDRESS
and HIGHEST ADDRESS.
FIRST EVENT, LAST EVENT, LOWEST ADDRESS and HIGHEST
ADDRESS are updated to show the range of time and addresses of errors
which have occurred for a DRAM. CRD CNT is simply the total count per
footprint. PAGE MAPOUT CNT is the number of pages that have been
marked bad for a particular DRAM.
5–14 System Troubleshooting and Diagnostics
