I don’t know how to contact these authors and maybe they won’t give out their code.
The discs were created with a tool called mvol (I only found IBM’s Move Volume). No need for extracting them either as all contents (SRC and binaries) are available in the sources. Creating discs or tapes is useful. The OS can also read IBM tapes. The only tools I know are the Hercules DASD tools.
I wonder, why both are spending so much time on IMP77 compilers. Even if they work and even if they were IMP80, I think someone can only run small, basic/text-like code + has to check and rewrite all IMP code and libs (depending on the hardware) + get a 32 bit linux.
As said the only way for me, running the relevant software on the EMAS site without rewriting all the code, are emulators. One for EMAS on ICL290xx, one for the APM machine, and maybe for the others like PDP-9/15, VAX etc. Christopher Lisle wrote one for the Fred / APM machine (for 68k Emulator Musashi by Karl Stenerud (MAME)), one for Amdahl (470 ?) and we have the MOUSES. We should make a call, find the authors and volunteers and start emulating projects.
Here is a PDF with screenshots of the APM including games like Frogger and Pacman