Re: i386/loader compiled with NOFORTH

John Baldwin wrote:
> > Yes, figured this out by myself already.  I've ended up
> > uncommenting the "hints" line in GENERIC config, everything
> > is OK now, and bzip2(1) also works, modulo the memory
> > restrictions -- only level 1 bzipping works that requires
> > ~250K of memory.
> >
> > John, is there a way to fix btx/loader/whatever so that
> > heap memory is not limited to 640K?
> 
> Not really.  At least, not easily.  We load the kernel up above 1mb,
> but we don't know how much memory lives up above 1mb and we assume
> that there is enough for the kernel and that's it.

You are limited to what you can access in real mode, without
Gate A20 (16M, at which point the address space wraps).

The best you might be able to get is another 384K, if you use
the INT15 function to map memory into the window between 640K
and 1M.  Assuming your BIOS supports it.  No way are you going
to get XMS/EMM support, without loading DOS parts.

This is probably not worth it.  Better to use gzip instead of
bzip2, and avoid the memory hogging.

Note that part of the workaround for the PSE/PG_G bug that was
posted is to load the kernel at 4M instead of 1M, so that it's
page aligned, and then use 4M pages for it up front.  That gives
you some more room, but it also increases the base memory size
requirements (probably unacceptably, for most people, which I
guess is why it was never committed by Bosko).

-- Terry