Booting questions ....

[Julian Elischer]

Willem Jan Withagen wrote:

> Scott Long wrote:
>
>> The loader has a protected mode environment.  It is apparently not all
>> that hard to port memtest86 into it.  I'd highly recommend doing this
>> rather than trying to hack up the early pmap initialization.
>
>
> Is that so.... I was unable to find that. :( can you give me a pointer??
>
> And like I wrote in the previous discussion. The algorithms are not 
> all that difficult to write. It is getting easy access to the memory.
> If you look at memtest86, you'll that they have to get a lot of work 
> done to get to the actual job: memory testing.
> And that only for the x86 type processors, which are already served by 
> memtest86.
>
> But reading your question, the answer would be:
>     too complex to get this figured out
>
> Then how about this:
>     what minimal parts of the kernel do I need to get at least:
>     1 cpu booted
>     flat memoryspace
>     printf working on the console (vga of serial)
>     areas which are taken by the above.
>     do I again get into pmap init stuff. 



you can not get all memory in a flat memory space with the advent of PAE.
you need to page it in and out of the address space.
I THINK the latest memtest86 does this..

I used to have a memory test that was based on the 1st stage bootlblocks
(The thing that loads the loader)
it was quite easy from that point..
you had full control of the memory and the disk and could load files and 
beat up anything.

>
>
> --WjW
>
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