ALGOL 68C
The ALGOL68C computer programming language compiler was developed for the CHAOS OS for the CAP capability computer at Cambridge University in 1971 by Stephen Bourne and Michael Guy as a dialect of ALGOL 68. Other early contributors were Andrew D. Birrell and Ian Walker.
The initial compiler was written in PSYCO (the Princeton SYntax COmpiler by Edgar T. Irons) and implemented by J.H. Mathewman at Cambridge. The language was called Z was subsequently morphed into ALGOL 68. ALGOL68C was built to develop the CAMbridge ALgebra system called CAMAL.
Subsequent work was done on the compiler after Bourne left Cambridge University in 1975. Garbage collection was added and the code base is still running on an emulated OS/MVT using Hercules.
The ALGOL68C compiler generated ZCODE output, that could then be either compiled into the local machine code by a ZCODE translator or run interpreted. ZCODE is a register-based intermediate language. This ability to interpret or compile ZCODE encouraged the porting of ALGOL 68C to numerous different computer platforms. Aside from the CAP capability computer the compiler was ported to systems including CMS, TOPS-10 and Z80.
Read more about ALGOL 68C: Popular Culture, Algol 68C and Unix, ALGOL 68C Extensions To Algol 68, Restrictions To The Language From The Standard ALGOL 68