Not all of the system's memory appears to be detected by the operating system

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Environment

SUSE Linux Enterprise Server 10
SUSE Linux Enterprise Server 9
SUSE Linux Enterprise Server 8
SUSE Linux Enterprise Desktop 10

Situation

x86-64 architecture (AMD64 or Intel EM64T) and system has 3.5 GB of memory or more

Not all of the system's memory appears to be detected by the operating system.

Resolution

A PC system needs to reserve a part of the memory addresses for input/output use by devices like extension cards. When a system has 3.5GB or more of memory, this can cause part of the memory to be inaccessible.

On some systems, the BIOS offers a feature known as "memory remapping" or "memory hoisting" which can reduce the amount of memory invisible to the system. This option however is known to cause problems for some configurations and should only be used after extensive testing of an identical system in a test environment.

Additional Information

A PC system needs to reserve a part of the memory addresses for input/output use by devices like extension cards. When a system has 3.5GB or more of memory, this can cause part of the memory to be inaccessible.
This problem is sometimes known as the "PCI memory hole" or simply as the "memory hole".

Formerly known as TID# 10099487

Disclaimer

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