Re: 4GB memory and Intel Dual-Core system
From: Roland Dreier
Date: Thu Oct 27 2005 - 15:54:46 EST
> BIOS-provided physical RAM map:
> BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
> BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
> BIOS-e820: 00000000000edbb0 - 0000000000100000 (reserved)
> BIOS-e820: 0000000000100000 - 00000000cec11000 (usable)
> BIOS-e820: 00000000cec11000 - 00000000cee12000 (ACPI NVS)
> BIOS-e820: 00000000cee12000 - 00000000cf68f000 (usable)
> BIOS-e820: 00000000cf68f000 - 00000000cf6e9000 (ACPI NVS)
> BIOS-e820: 00000000cf6e9000 - 00000000cf6ed000 (usable)
> BIOS-e820: 00000000cf6ed000 - 00000000cf6ff000 (ACPI data)
> BIOS-e820: 00000000cf6ff000 - 00000000cf700000 (usable)
If that's the full e820 map, then I guess the question is why did the
BIOS not tell you about any memory above 0xcf700000?
And I have no idea why it wouldn't. For comparison, here's an AMD64
system I have with 4 GB of RAM. Notice how it put a big chunk of RAM
above 4G:
BIOS-e820: 0000000000000000 - 0000000000098800 (usable)
BIOS-e820: 0000000000098800 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000c2000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 00000000bff20000 (usable)
BIOS-e820: 00000000bff20000 - 00000000bff2a000 (ACPI data)
BIOS-e820: 00000000bff2a000 - 00000000bff80000 (ACPI NVS)
BIOS-e820: 00000000bff80000 - 00000000c0000000 (reserved)
BIOS-e820: 00000000d8800000 - 00000000d8800400 (reserved)
BIOS-e820: 00000000d8801000 - 00000000d8801400 (reserved)
BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
BIOS-e820: 00000000fec00000 - 00000000fec00400 (reserved)
BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
BIOS-e820: 00000000fff80000 - 0000000100000000 (reserved)
BIOS-e820: 0000000100000000 - 0000000140000000 (usable)
- R.
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