An academic question.
What makes the writing of a non ibm powerpc
compiler impossible on the iseries?
===> I don't think it is impossible. (as to the benefits,
I'm not so sure).
The pgm validation value looks to be one. It
prevents you from restoring your pgm after a system crash.
===> 1) the system doesn't crash
2) Even if it did, there is no need to restore your
program
3) Computation of the PVV is possible
Is there sufficient undocument knowledge of
the pgm hdr, passed on over the years from guru to guru, to create a working
pgm object?
===> yes, but there are better ways (Attaching your code
to an existing, dummy program).
The undocumented ibm extensions to the powerpc assembler
code. It should be doable to figure that out, right?
===> most them are already "figured out"
The system state, user state issue. Would this rogue
risc compiler be able to create the system state segments of the pgm
object?
===> you probably mean "system domain"
objects.
1) it is not necessary for the pgm to be system
domain
2) you can easily give the pgm the system domain
attribute
3) you probably don't want to as you cannot call your
program from a user domain program.
You probably meant to ask if you can write protect the
program as normal AS/400
programs are. This is not worth the trouble (for a rogue
compiler!)