Service manual

3-86 AlphaServer GS80/160/320 Service Manual
3.11 Error Detection
Error detection is distributed throughout the system.
Figure 3– 2 Core System Error Detectors
Figure 3–2 is a block diagram showing the data error detectors in the system.
There are three types of errors:
• Correctable errors are detected either by the system or by a CPU. If the
error is detected by the system, an error interrupt is generated and
delivered to the system primary CPU, the data is corrected at the
destination wherever that may be, and PALcode builds a 620 system
correctable error frame that is deposited in the error log. If the CPU detects
the error, an error interrupt is generated for that CPU and PALcode builds
a 630 processor correctable error frame that is deposited in the error log.
• Uncorrectable errors are detected either by the system or by a CPU and
are fatal. If the error is detected by the system, an error interrupt is
generated and delivered to the system primary CPU, the system crashes,