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List:       linux-vm
Subject:    Re: LINUX-VM Digest - 4 Jul 1999 to 5 Jul 1999 (#1999-20)
From:       Linas Vepstas <linas () LINAS ! ORG>
Date:       1999-07-07 4:06:30
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It's been rumoured that Rich Greenberg said:
> I am not sure which is better, but IMHO the modified 3CARD LOADER and
> TXT cards are the way to go.  Could you modify the process that creates
> the image to create the TXT cards instead?  Save us a conversion step.

I think Rick & Arty may be coming to realize that its a tad harder than this.
First, I use the standard gnu tools to compile & link the executable together.
The executable is just an ELF-format executable, produced by the 'ld' linker.
It doesn't make sense to modify the linker or to break adherence to the ELF
spec.  There's not a lot of control one can exert on that stage.

Yesterday/today we discovered that the new linker I'm using has moved
stuff around.  It now writes out three program parts, each of which needs
to be moved into place during the load.  The ELF header describes where to
find them & where to move them too, (and also the lengths etc.).
Its not *hard* to do this, its just another important stage.

BTW the ELF header is described in chapter 3 of the ELF (sysv) ABI at
http://www.sco.com/developer/devspecs/

As a related matter, at some point we need to arrange to pass a command line
somehow to the kernel from the loader.

> you in 24 bit addressing mode.  The first 2 things your kernal should do
> after receiving control are:
>  1) Load a PSW with relocate, addressing modes etc as you want them.

Yes, I'm taking steps to boot up no matter what the environment.

>  2) Initialize low memory, new PSWs etc.

That's pretty much taken care of (mostly).

--linas

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