Booting questions ....

[Willem Jan Withagen]

Julian Elischer wrote:

> 
> 
> 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 got lost in all the code spins in memtest86...
Ant thinking that there would be a simpler aproach, I stopped trying to 
understand all.

> 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.

Eeek, boot1 is ASM, and boot2 is fully loaded with v86 on i386....
And now I come to think of it, it would not really work for me, since I'm 
using GRUB to actually get directly to /boot/loader. But that's rather 
specific in my case.

--WjW