Re: [OT] Documentation for PC Architecture

From: Paolo Ornati
Date: Mon Aug 18 2003 - 16:16:19 EST


>
> > Curiosity: since the memory addresses from 640KB to 1MB are reserved for
> > memory mapped I/O (video memory) and BIOS ROM... the corrispondent range
> > in
>
> uh oh ...
>
> > the REAL MEMORY isn't usable and so we lost 384KB of memory. Is this
> > right?
>
> for DOS, withouth upper memory manager yes ;)

I'm talking about an OS in protected mode... in any case how can I access to
this memory region if it's mapped for other things?

I've done some tests with a simple kernel which I wrote: all that region
(except video memory at 0xb8000) results "read only"...

So I THINK YOU mean: "you can use more than 640KB in real mode using a memory
manager that "remap" 0xC0000 (for example) to 0x100000 or something like it"

Right?

bye,
Paolo

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