Date: Fri, 05 Nov 2004 00:54:54 +0100 From: Willem Jan Withagen <wjw@withagen.nl> To: Julian Elischer <julian@elischer.org> Cc: Scott Long <scottl@freebsd.org> Subject: Re: Booting questions .... Message-ID: <418AC14E.4040005@withagen.nl> In-Reply-To: <418ABA47.7080306@elischer.org> References: <418AB176.9030604@withagen.nl> <418AB649.80809@freebsd.org> <418AB888.7070305@withagen.nl> <418ABA47.7080306@elischer.org>
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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
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