Apple Xserve - Apple Xserve - Manual (Page 39)

Appendix AXD Tools Test Reference 39
Memory Tests
All memory tests are listed under Memory. These tests are described here.
Simple Memory Tests
Simple memory tests test the first 2.5 GB of memory. To test all memory, run extended
memory tests.
Even though simple memory tests don’t test all memory, run these tests to detect
intermittent memory issues.
In AXD EFI tools, all memory tests (simple, multicore, and extended) are grouped under
Memory tests.
Note: The time required to complete memory tests correlates to the size of memory
being tested. These estimates are based on testing 1 GB of memory.
Test Estimated completion time Description
Address as Data 5 seconds Tests memory using the
memory address as data.
Patterns 25 seconds Tests memory using different
data patterns.
Marching Ones and Zeros 15 seconds Tests memory by walking 1s and
0s up and down memory.
Knaizuk Hartmann 10 seconds Tests memory using this
algorithm.
MOD3 30 seconds Tests memory using this
algorithm.
March U 2 minutes Tests memory using this
algorithm.
Random 15 seconds Uses pseudo-random values.
Block Checkerboard 32 10 seconds Alternates 32-bit words with all
1s and all 0s, and then with all
0s and all 1s.
Bit Checkerboard 32 10 seconds Alternates bits with all 1s and
all 0s, and then with all 0s and
all 1s.
Sequential Byte Block 32 14 minutes Fills all bytes sequentially with
patterns starting at 0x00 and
ending at 0xFF.
Walking One 32 5 minutes Walks 1s up and down memory.
Walking Zero 32 5 minutes Walks 0s up and down memory.