S-algol was designed by Ron Morrison and extended by Pete Bailey, Fred Brown, Paul Cockshott, Ken Chisholm, and Al Dearle.
These extensions were additional standard functions that provide a persistent heap that survives termination of PS-algol programs.
PS-algol was the world's first fully implemented persistent programming language,[3] and had many users both in academia and, notably, in International Computers Limited (ICL) research labs.
[4][5] PS-algol was conceived by chance, when Ron Morrison was on sabbatical at the University of Edinburgh and met Malcolm Atkinson.
Morrison, whose interest in general-purpose programming had led to the development of S-algol, a general purpose teaching language, realised that S-algol's type system would more easily allow adding orthogonal persistence.