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Chapter 1
Memory Sparing Technology
This portion just guide you the outline of memory sparing and mirroring technology.Memory sparing uses an
online spare bank to provide DIMM fail-over capabilities when a pre-defined threshold of single-bit correctable
errors is reached. The pre-defined threshold is set in BIOS and cannot be changed by the user.
DIMM Capacity and Configuration Requirements
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Memory is 4-way interleaved and as a result the DIMMs must be installed in banks consisting of 4
DIMMs per bank.
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The DIMMs in a bank must be of the same capacity, manufacturer and have the same SPD
characteristics. No mixing of memory DIMMs is allowed.
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Bank #1 and Bank #2 is defined Active bank. Bank #3 is defined spare bank. For available memory
sparing function, DIMM must install in active bank and spare bank.
Below table list the install bank of memory sparing:
NOTE:
The spare bank will be removed from the memory pool and held as a spare, for instance, if 12 x 1 GB
DIMMs are installed, only 8 Gigabytes of that 12 Gigabytes is available for use by the operating system.
How Memory Sparing Works
In normal mode of operation, system reads/writes memory data to active bank (Bank #1/Bank #2). The system
does not read/write memory data to spare bank (Bank #3). Bank #3 does not have memory data before
memory data sparing begins.
Memory sparing function moves memory data from error bank to spare bank, if Correctable error's counts
exceed threshold value. After moving memory data, System degenerate error bank and records error log. And,
System should blink system status LED.
Memory sparing does not recover uncorrectable error. Therefore, if system detects Uncorrectable error,
system will assert fatal error and the system will halt.If system sets memory sparing function, system could not
use memory mirroring function at a same time.
Bank #1(Active Bank)
Bank #2(Active Bank)
Bank #3(Spare Bank)
4 DIMM
configuration
Install
Not Install
Not Install
Not Install
8 DIMM
configuration
Install
Not Install
Install
Available
12 DIMM
configuration
Install
Install
Install
Available