Lenovo ThinkPad 770 Technical Reference Manual for the ThinkPad 770 - Page 39

System Memory Map, the variable

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System Memory Map Memory is mapped by the memory controller registers. Figure 2-10 on page 2-17 shows the memory map for a correctly functioning system. Memory can be mapped differently if POST detects an error in system board memory or RT/CMOS RAM. In the figure, the variable x represents the number of 1 MB blocks of system board memory starting at or above the hex 100000 boundary. Hex Address Range 00000000 to 0009FFFF 000A0000 to 000BFFFF 000C0000 to 000C9FFF 000C8000 to 000EFFFF 000F0000 to 000FFFFF 00100000 to (00100000 + x MB) FFFF0000 to FFFFFFFF Function 640 KB system board RAM Video RAM System board video BIOS ROM mapped to RAM Channel ROM 64 KB system board ROM mapped to RAM x MB system board RAM 64 KB system board ROM (same as 000F0000 to 000FFFFF) Figure 2-10. System Memory Map System Board 2-17

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System Memory Map
Memory is mapped by the memory controller registers.
Figure
2-10 on page
2-17 shows the memory map for a correctly
functioning system.
Memory can be mapped differently if POST
detects an error in system board memory or RT/CMOS RAM.
In the
figure, the variable
x
represents the number of 1 MB blocks of
system board memory starting at or above the hex 100000 boundary.
Figure
2-10.
System Memory Map
Hex Address Range
Function
00000000 to 0009FFFF
640 KB system board RAM
000A0000 to 000BFFFF
Video RAM
000C0000 to 000C9FFF
System board video BIOS ROM mapped to
RAM
000C8000 to 000EFFFF
Channel ROM
000F0000 to 000FFFFF
64 KB system board ROM mapped to RAM
00100000 to (00100000 +
x
MB)
x
MB system board RAM
FFFF0000 to FFFFFFFF
64 KB system board ROM
(same as 000F0000 to 000FFFFF)
System Board
2-17