[Unix-jun72] UNIX V1 bootstrap

[wkt@tuhs.org (Warren Toomey)]

On Sat, May 17, 2008 at 06:04:48PM -0700, James A. Markevitch wrote:
> For building under UNIX itself, there are a variety of strategies.  Here
> is my list, in order of preference:
> 
> 2. Modify the V2 assembler to produce V1 binaries.

I'm going to take a "devil's advocate" stance here, and argue to keep the
existing "as" binary untouched.

We have a bunch of userland executables which come from a point in time
after V1, including "as" and the C compiler. While we have kernel source
which is V1 on paper, we already have had to modify it to suit the userland
tools and the simulator. We will never get to a "pure V1" setup, so I would
prefer to see us aim for a "just after V1" system.

I'm fairly confident that, as V1 morphed into V2, they kept support for
0405 and 0407 in the kernel, but migrated the tools and boot chain towards
0407. Given we can't get back to pure V1, it would not hurt for us to have a
boot chain which can deal with 0407 headers.

Cheers,
	Warren