Service manual

DECevent Error Log 4-17
4.5.2 Machine Check 620 Error
Machine check 620 errors are nearly always soft errors; that is, they do
not cause the system to crash. Correctable write data errors (CWDE)
on CSR writes are the exception.
Example 4-6 shows a sample machine check 620 error. In this case, all nodes on
the TLSB are presented in the error log entry. The steps in Table 4-4 isolate
the error and the FRU most likely responsible.
Table 4–4 Parsing a Sample 620 Error (Example 4-6)
➊
This line identifies the error log entry as a machine check 620 error.
➋
The parse tree for machine check 620 errors starts with the DC_STAT
register. The next branch on the parse tree is C_STAT.
DSTREAM_MEM_ERR is set.
➌
The TLBER register is next in the parse tree. CORRECTABLE READ
DATA ERROR is set.
➍
The TLBER register on the memory module is next in the parse tree.
CORRECTABLE READ DATA ERROR is set.
➎ The error log identifies the SIMM where the error occurred as J22. UNIX
lists each occurrence of a corrected read data error. Before replacing the
SIMM, you would probably want to examine other 620 entries to see if the
error on SIMM J22 was repeated.
Example 4-6 Sample Machine Check 620 Error Log Entry
**** T3.1 ****** ENTRY 1 ***********************
Logging OS 2. Digital UNIX
System Architecture 2. Alpha
Event sequence number 2.
Timestamp of occurrence 15-JUN-1999 20:05:32
Host name warp5
System type register x0000000C AlphaServer 8x00
Number of CPUs (mpnum) x00000004
CPU logging event (mperr) x00000002