Hi Chris,

On 16 Feb 2001, Chris G. Demetriou wrote:
> imago@kabel065011.kabel.utwente.nl (Reinoud Zandijk) writes:
> > This means ofcource that compatibility with the old bootloader is broken
> > .... I'm thinking of a complilation option to allow kernels still to be
> > made for the old bootloader by selecting a different bootconfig.h and
> > patching up the old rpc_machdep.c if desired....
>
> perhaps this is a naive question, but why would the kernel detect one
> version or the other, convert old to new if necessary, _by default_.

Well.... i dont know if you have seen the difference in the two
rpc_machdep.c but yes they are VERY different and pity enough VERY
different.

The basic difference is not as much as how they pass on data (well yes in
the new version) but on how their memory map and booting goes... the old
one relies on rhe RISC OS page tables being hacked and relocates itself in
the running kernel and the new one gets up nice and clean on the correct
place... it makes it RO version independent...

ebsa, rc7500, shark and cats are not affected with it... their machdep's
only need a little addition thats all.

> You should be able to compile that code out, but by default new
> kernels should interoperate with old boot loaders unless things are
> irreparably broken in the way the old boot loaders pass in data...

They really can't :(( ... but the two bootloaders can easily exist next to
eachother so a netbsd.old kernel can be booted with the old bootloader and
a netbsd kernel can be booted by the new one....

Cheers,
Reinoud