Re: [Modularkernel-developer] PhysicalKernelStart, PhysicalManagedStart

[Daniel O. <mus...@go...>]

Am 09.04.2010 23:17, schrieb Tomas Klacko:
> Hi,
>
> in physical_memory.c, are PhysicalKernelStart and PhysicalManagedStart
> always going to have the same value? (0x100000)
>
> Tomas Klacko
>
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They can, as it is at the moment, but it is not necessary.
The two variables describe two completely different things.
The one is the start of the kernel, which is somehow a constant thing, 
because loading to 1 MB mark is the "standard" for kernels.

The PhysicalManagedStart is the value describing at which point in 
memory we start tracing whether it is used or not. So at the moment, we 
cannot say whether memory before 1 MB is used or not.

I am thinking to change that, because it is somehow nonsense to not 
manage a part of the physical memory.

Its a relict from previous code, where I thought (which was wrong, as I 
know now) that PHYSICAL memory under 1 MB is needed for DMA, but in fact 
it is VIRTUAL, so there should be no problem managing all physical 
memory in the same way :)