8

Error Detection and Error Handling

This chapter gives an overview of the 21264/EV67 error detection and error handling mechanisms, and is organized as follows:

Data error correction code

Icache data or tag parity error

Dcache tag parity error

Dcache data correctable ECC error

Dcache store second error

Dcache duplicate tag parity error

Bcache tag parity error

Bcache data correctable ECC error

Memory/system port data correctable ECC error

Bcache data correctable ECC error on a probe

Double-bit fill errors

Error case summary

Table 8–1summarizes the 21264/EV67 error detection.

Table 8–1 21264/EV67 Error Detection Mechanisms

Component

Error Detection Mechanism

 

 

Bcache tag Bcache data array Dcache tag array Dcache duplicate tag array Dcache data array

Icache tag array Icache data array System port data bus

Parity protected.

Quadword-ECC protected.

Parity protected.

Parity protected.

Quadword-ECC protected, however this mode of operation is only supported in systems that have ECC enabled on both the system and Bcache ports.

Parity protected.

Parity protected.

Quadword-ECC protected.

Alpha 21264/EV67 Hardware Reference Manual

Error Detection and Error Handling 8–1

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Compaq specifications Error Detection and Error Handling, 21264/EV67 Error Detection Mechanisms