Author Topic: Question on PM memory test  (Read 10185 times)

Offline nindecksai

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What does the "PM Memory" test do? 


Offline fwilson

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nindecksai,

Here is a description taken from the manual;

Advanced Memory Tests
This category tests the system Random Access Memory (RAM) in protected mode (PM). Advanced memory tests are
similar to standard memory tests except they support testing a much larger configuration of memory (up to 64GB) and
will still run in a 32-bit environment.The length of the test depends on the amount of installed memory. All types of
memory chips are tested, as are all module types: DRAM, SDRAM, EDO, SIMM, DIMM, SODIMM, and so on. All
memory tests also support RAMBUS memory, checking the RAMBUS configuration and warning of disabled devices
or invalid configurations.
Address Fault
This test uses unique addressing to determine if the memory address decoder is prone to specific failures. This is
accomplished by controlling the order in which patterns are read and written to memory. The types of failure this test
looks for are:
• A disconnected address.
• A misdirected address.
• Multiply selected addresses.
• Multiply selected cells.
Extended Advanced Pattern Test
This test fills a memory location with a test pattern, then reads the memory location to verify the pattern was written
correctly. When done testing a memory location, it moves on to the next memory location. Test passes occur from the
first available memory address to the highest available address and back to the first available address.
This test runs with the CPU in protected mode to provide 32-bit operations. The main differences between the Advanced
Pattern and PM Advanced Pattern tests are speed and test coverage. The Advanced Pattern test is much slower than the
PM Advanced Pattern test but provides significantly more test coverage..
The main difference between the Short Advanced Pattern test and the Extended Advanced Pattern test is the number of
patterns and test phases used. For this reason, the Extended Advanced Pattern will run significantly longer than the Short
Advanced Pattern but has the potential to uncover significantly more defects.
Memory Fault
This test uncovers memory bits that are affected by a “stuck-at” fault. Sometimes referred to as a “sticky bit”, a “stuck-at”
fault is an error with the memory module circuitry that causes a bit to permanently retain its value when changed. Once
the bit obtains a specific value (0 or 1), it will retain this value no matter what is written to the location. This test uncovers
“stuck-at” faults by writing a known pattern across all testable memory, then reading and comparing what was read to
what was written. If the test detects a mismatch between the written and read data, it records the error in the test log and
logs as Failed.
Short Advanced Pattern Test
This test fills a memory location with a test pattern, then reads the memory location to verify the pattern was written
correctly. When done testing a memory location, it moves on to the next memory location. Test passes occur from the
first available memory address to the highest available address and back to the first available address.
This test runs with the CPU in protected mode to provide 32-bit operations. The main differences between the Advanced
Pattern and PM Advanced Pattern tests are speed and test coverage. The Advanced Pattern test is much slower than the
PM Advanced Pattern test but provides significantly more test coverage..
The main difference between the Short Advanced Pattern test and the Extended Advanced Pattern test is the number of
patterns and test phases used. For this reason, the Extended Advanced Pattern will run significantly longer than the Short
Advanced Pattern but has the potential to uncover significantly more defects.significantly more defects.
“Integrity is doing the right thing, even if nobody is watching.”  ~ J.C. Watts

Offline nindecksai

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Per usual the diagnostics utility freaks out when it encounters anything sufficiently out of standard PC spec.  The IBM Thinkpad R61 I'm working will need the bios patched to the most recent version and should have that done anyway per usual maintenance; IBM likes making out of spec merch, then again laptops are quasi-spec from factory as is in some spots no matter what the brand is.

I've always found the PC Doc memory test to be sufficient for spotting 90% of the common memory errors and Memtest X86+ for the other 9% (Dual-channel dimm module chip count/single vs dual sided vs dual stack mismatch, incorrect SPD timing values, DIMM Damage due to incorrect SPD timing, etc).  The other 1% you can't test with a utility.

Thanks!



Offline fwilson

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nindecksai,

Thanks for being a customer!

-Fred
“Integrity is doing the right thing, even if nobody is watching.”  ~ J.C. Watts