Memory Test - Toshiba PORTEGE M400 Maintenance Manual

3 Tests and Diagnostics
3.8

Memory Test

To execute the Memory Test, select 2 from the DIAGNOSTIC TEST MENU, press Enter
and follow the directions on the screen. Move the highlight bar to the subtest you want to
execute and press Enter.
Subtest 01 Conventional memory
This subtest writes a constant data to conventional memory (0 to 640 KB),
then reads the new data and compares the result with the original data.
Subtest 02 Protected mode
NOTE: The CONFIG.SYS file must be configured without expanded memory manager
programs such as EMM386.EXE, EMM386.SYS or QEMM386.SYS. Also, the
HIMEM.SYS must be deleted from the CONFIG.SYS file.
This subtest writes constant data and address data (from 1MB to maximum
MB), and reads the new data and compares the result with the original data.
Subtest 03 Protected mode (cache off)
This subtest executes the same way as the subtest02 with the cache off.
Subtest 04 Cache memory (on/off)
To test the cache memory, a pass-through write-read comparison of '5Ah'
data is run repeatedly to the test area ('7000':'Program size' to '7000':'7FFF' (32
KB)) to check the hit-miss ratio (on/off status) for CPU cache memory. One
test takes 3 seconds.
Number of misses < Number of hits → OK
Number of misses ≥ Number of hits → Fail
Subtest 05 Stress
Data (from 1MB to the maximum MB) is written from the 16KB write buffer
to the 16KB read buffer and compared the data in the buffers. The read buffer
starts from 0001 and the comparison is continued with the following read
buffer addresses: 0001, 0003, 0005, 0007, 0009, 000b, 000d and 000f.
3-24 [CONFIDENTIAL] PORTEGE M400 Maintenance Manual (960-541)

3.8 Memory Test