Doug Harvey wrote:
Very much a newcomer here but have been following this discussion
with interest, and appreciate both sides of the discussion, but I
don't think the program should be updated.
If it WAS, and tomorrow (somehow) you stumbled across an old 1980's
era mainframe in a barn,
HA! In your dreams! :)
you should be able to install and run MVS 3.8j on it.
If this program were updated to use the TPROT instruction,
that wouldn't work.
Sure it would! As long as you did the update *correctly* (sensibly) of course.
Check for the existence of the 'TPROT' instruction at startup (IPL) and set a flag somewhere that IEAVEVAL can then easily check. If the flag is on ('TPROT' is available), do it the newer, better, *preferred* way. Otherwise fall back to doing it the older less efficient 'CS' way.
I don't know how many instructions there are, or when new
instructions were added, but it would be pretty cool if (say)
Hercules could be started to run with the 01-May-1980 CPU
instruction set, 01-July-1990 CPU instruction set, etc.
That would be an administrative nightmare and something that would almost *certainly* NEVER happen. (That of course is a prediction based on my years as a Hercules developer, and NOT a promise. Stranger things have happened. But seriously, I *strongly* doubt it will EVER happen.)
--
"Fish" (David B. Trout)
Software Development Laboratories
mail: fish@...
