Service manual

5-50 AlphaServer 4000/4100 Service Manual

5.4.9 Broken Memory

Step 10

Refer to the following sections.

For a Read Data Substitute Error (uncorrectable ECC error)

When a read data substitute (RDS) error occurs, determine which memory module

pair caused the error as follows:

1. Run the memory diagnostic to see if it catches the bad memory. If so, replace

the memory module that it reports as bad.

2. At the SRM console prompt, enter the show mem command.

P00>>> show mem

This command displays the base address and size of the memory module pair for

each slot.

Read the configuration packet, found in the error log, to retrieve the base

address and size of the memory module pair.

3. Compare this address to the failing address from the MC_ERR1 and MC_ERR0

Registers to determine which memory slot is failing.

4. Replace both memory modules (high and low) for that slot. For an RDS error,

there is no way to know which memory module (high or low) is bad.

For a Corrected Read Data Error (CRD)

When a CRD error occurs, determine which memory module pair caused the error as

follows:

1. At the SRM console prompt, enter the show mem command. This command

displays the base address and size of the memory module pair for each slot.

P00>>> show mem

2. Compare this address to the failing address from the MC_ERR1 and MC_ERR0

Registers to determine which memory slot is failing.