Toshiba T6400, Maintenance Manual

Page: 67 / 198

3-13
3.5 Memory Test
To execute the Memory Test , type 2 from the DIAGNOSTIC TEST MENU, press Enter , and
follow the directions displayed on the screen. The Memory Test contains five subtests that test the
following T6400 memories: RAM constant data, RAM address pattern data, RAM refresh (real
mode), protected mode, and memory module. Select the number corresponding to the subtest you
want to execute and press
Enter
.
Subtest 01 RAM Constant Data
This subtest writes constant data FFFFh, AAAAh, 5555h, 0101h, and 0000h to
conventional memory (0 to 640KB). The constant data is then read from conven-
tional memory and compared to the original data.
Subtest 02 RAM Address Pattern Data
This subtest writes address pattern data created by eXclusive-ORing (XORing) to
the address segment and address offset in conventional memory (0 to 640KB). The
address pattern data is then read from conventional memory and compared to the
original data.
Subtest 03 RAM Refresh (Real Mode)
This subtest writes a 256-byte unit of constant data (AAAAh and 5555h) to conven-
tional memory (0 to 640KB). This data is then read from conventional memory and
compared to the original data.
NOTE: The size of the data being read and written to conventional memory causes a short
delay between write and read operations.
Subtest 04 Protected Mode
This subtest writes constant data FFh, AAh, 55h, 00h and address data to extended
memory (addressed 100000h to the maximum address). The data is then read from
extended memory and compared to the original data.