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Re: basic memory division question

On Tue, Oct 10, 2000 at 01:47:39AM -0400, kamesh jayachandran wrote:
> Hello,
> It is the question in my mind for long.Even though it may be trivial ,i think 
> of asking it to the group.
> The question is
> How the Physical Memory is divided in among USER and KERNEL space.

It's not divided strictly. Both of them allocate memory from the same
pool of pages created at startup.

What is divided is the virtual memory 0->0xc0000000 for user and the
rest for the kernel.

> I mean the 
> amount of memory allocated for both.And starting address of both the Kernel 
> space and User Space.
> Longtime before i have seen in the list that Kernel is getting loaded at 
> 0xc0010000+X where X is getting translated to physical address.

That is a virtual address. Since linux uses 1:1 virtual->physical mapping
0xc0000000 virtual = 0 physical, scheme and the kernel gets loaded at
0x100000 physical, it appears at 0xc0100000 virtual once the processor
is switched to virtual mode.

More details on this beyond the scope of a mail - you might want to
read some linux kernel book.