A Short History of Empire by Chris Gray

   The first widely available version of Empire was written by Peter Langston,
who also wrote the 'wander' adventure game system. It was available, as
far as I know, only in PDP-11 object code format for running under UNIX
Version 6. I played two games with that version on a PDP-11/45 at the
University of Alberta. The game appears to have been popular within the
North American UNIX community, and its absence on other machines was a sore
point. Tom Fisher took exception to this and proceeded to de-compile the
object module into C. His version is now available and will run on most
UNIX systems. It is difficult to modify, however, because much of its
structure reflects the decompilation process - it is a maze of labels and
goto's. It also reflects the memory limitations of the PDP-11 and is
structured as a set of 7 different programs which are accessed as overlays.
Another version of Empire, presumably a re-implementation, has been done
by people at Berkeley (I think). I've never seen this version, so can't say
much about it, except to say that it has been augmented with farms,
bombers, tanks, nuclear weapons, etc. I have recently heard of another
project to re-implement Empire, in which the sources will explicitly NOT be
made available. The sources to this Draco version are available now. Chris
Thierman took it upon himself to implement Empire for the University of
Alberta's Amdahl mainframe about 18 months ago. The project proceeded, but
was never completed. We both bought Amigas about that time and eventually I
had Draco ported and Chris was using it a bit. He decided to port Empire to
the Amiga and requested my aid in doing a translation from QC (a compiler of
mine for the 360/370 series) to Draco. I agreed and soon found myself
headlong in the implementation of Empire.