The UCSD "Computer Scientists" were a small group of undergraduates working in Ken Bowles' lab. We were supposedly following Professor Bowles' directions but he was a fairly conservative physicist and we had lots of radical ideas - fortunately he was tolerant. The p-code was not just machine independent - by careful design it was approximately 1/4 the size of native code on those early 8 and 16-bit microprocessors, allowing us to effectively almost quadruple the amount of code we could fit in 64K - minus the interpreter which was 8K of machine code and minus another 8K on PDP-11s for I/O space. We would also use native code for hotspots without appreciably expanding code size. This key idea is what allowed us to have a high-level OS and development environment on those dinky machines when everyone else was compromising quality to get things to fit. Alas, CopyLeft had not yet been invented, the UC sold the P-System and we lost legal access to the code we'd written.