>>>>> One Without Reason writes:

Sridhar> That's the problem.  There are a couple of others, as well.  Some user
Sridhar> software apparently makes use of instructions not present on the earlier
Sridhar> generation systems too.  I'd rather just make it possible for a single
Sridhar> kernel to be able to boot any of these machines.  Far in the future, even
Sridhar> 64-bit support for the zSeries.

	Running G4 applications on earlier systems will not be trivial.
For UP, your goal of a single kernel is possible.  For MP, G4 will be a
dependency. 

Sridhar> Actually, I am basing my work on the Linux-S/390-Vintage work.  They did
Sridhar> quite a bit of preliminary stuff looking into recompilation before they
Sridhar> settled on emulation of the missing stuff.  It would indeed be neat to get
Sridhar> GCC onto the S/370.  I might take a crack at it after I get the
Sridhar> older-generation S/390 stuff in.  Unless, that is, you want to do it. 8-)

	GCC already does work on S/370 -- on z/OS aka OS/390 aka MVS.
That is what the "i370" port did.  Dave Pitts added support for MVS Unix
System Services aka Open Edition (X/Open / Unix branded MVS).  Linas
Vepstas had some Linux for S/370 changes based on that work.  It would be
much better to merge the S/370 work in the s390 port instead of keeping
two ports around.

David