ALGOL 68S
ALGOL 68S was designed as a subset of ALGOL 68 in order to permit single-pass compilation. It was mostly for numerical computation.Implementations
A compiler for ALGOL 68S was available for the PDP-11, written in BLISS. The multiprocessor version designed for the C.mmp has been preserved at the PUPS archive of the PDP11 Unix Heritage society, c.f. .
Charles H. Lindsey has another ALGOL 68 implementation called ALGOL 68S for Sun3, Sun Sparc, Sun Sparc, Atari ST and Acorn Archimedes, c.f. Chief differences from ALGOL 68