Re: Potpurri ?

>I tried everything on my 486, before I got it to use shared memory.
>And to disallow bios to remap shadow memory - was one of the things
>I did. If that matters at all, - I don't know. I just passed a note
>about it.
>
>

How did you disallow the BIOS from remapping the shadow RAM? I would like to
know in case I find that I need to do this.

Patrick

-----Original Message-----
From: Arne Chr. Jorgensen <instel@...>

>
>When the machine boots, it uses BIOS. It count up the memory, and
>make everything available for DOS, - which then boots up, and then
>this again may boot up Windows.
>As my little story told, Bios is still used as the foundation to it
>all. But reading from EPROM (read only memory on the main board ) is
>much slower than reading from RAM. So it copies itself to RAM, and
>uses this image instead. But by doing so, it will steal a part of
>the available RAM memory. On the old 8088/86, there was a memory
>limit to 640K bytes. IO, and BIOS used the part above that, but the
>limit was 1024K bytes. (With 80286, you could address memory above
>this.)
>There is unused holes in this memory space, and you could use some
>RAM installed above 640K for ram disk, or other stuff. Here is
>where parts of the BIOS "ram" image could go, -or it could use the
>same physical address, but in the "ram" memory space. And the Bios
>setup, has options to do some tricks here, by remapping the entire
>memory space that other programs will see.
>
>I wish I could say that 2+2=4, but I can't. I don't know if Linux
>is using Bios after it is loaded, and I don't know how a remapped
>memory space would be seen like by Linux. But I think it don't
>bother anyway, because it uses another way to deal with all of
>this. Linux will only run on 80386, and uses another memory
>management - protected mode.
>
>I tried everything on my 486, before I got it to use shared memory.
>And to disallow bios to remap shadow memory - was one of the things
>I did. If that matters at all, - I don't know. I just passed a note
>about it.