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Re: How is size of kernel found? What exactly do the memory numbers mean
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From: |
Yoshinori K. Okuji |
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Subject: |
Re: How is size of kernel found? What exactly do the memory numbers mean? |
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Date: |
Fri, 25 Jan 2002 18:11:20 +0900 |
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User-agent: |
Wanderlust/2.6.0 (Twist And Shout) SEMI/1.14.3 (Ushinoya) FLIM/1.14.3 (Unebigoryoae) APEL/10.3 Emacs/20.7 (i686-pc-linux-gnu) MULE/4.0 (HANANOEN) |
At Thu, 24 Jan 2002 22:58:08 -0600,
Phil Frost wrote:
> gcc, ld, or 2 ELF specs that I looked at. An objdump -t of my kernel
> reveals that there is no _end symbol. Is it possible at all to obtain
> the size of the kernel?
Are you using your own linker script?
> Also, I am unable to find the exact meaning of the mem_lower and
> mem_upper members of the multiboot info passed to the kernel in EBX. On
> a four meg system, 639KB lower and 3072KB of upper is reported.
> 3072+639=3711, 3.62MB. Where did the other 385KB go?
It's ROM space used by BIOS.
> this could be a defective BIOS, I highly doubt it. Do these memory
> numbers indicate unused RAM, after the loading of modules, excluding the
> IDT, BIOS data areas, and all else? Or, do they specify something else?
They just specify RAM. That exact meaning is BIOS-specific, I think.
Okuji