Memory Test - Toshiba 650CT Maintenance Manual

3.5

Memory Test

To execute the Memory Test, select 2 from the DIAGNOSTIC TEST menu, press Enter and
follow the directions displayed on the screen. Move the highlight bar to the subtest you want
to execute and press Enter.
Subtest 01 Constant data (real mode)
This subtest writes a 256-byte unit of constant data to conventional memory (0
to 640 KB), reads the new data and compares the result with the original data.
The constant data is FFFFh, AAAAh, 5555h, and 0000h.
Subtest 02 Address pattern data (real mode)
This subtest writes address pattern data created by the exclusive-ORing
(XORing), to the address segment and address offset in conventional memory
(program end to 640 KB), then reads the new data and compares the result
with the original data.
Subtest 03 Refresh (real mode)
This subtest writes a 256-byte unit of constant data to conventional memory (0
to 640 KB), then reads the new data and compares the result with the original
data.
The constant data is AAAAh and 5555h.
NOTE: There is a short delay between write and read operations, depend-
ing on the size of the data.
Subtest 04 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 to extended memory (maxi-
mum address 100000h), then reads new data and compares the result with the
original data.
The constant data is FFh, AAh, 55h, and 00h.
650CT
3-9