The work for SIGAI was carried out by the University of Edinburgh and all the software run on the DEC10 KL at the Edinburgh Regional Computer Centre (ERCC) that managed the DEC10. The SIG had two programmers that supported the activity.
SIGAI was originally formed to support and extend the languages such as POP-2, LISP and PROLOG used by the AI community on the DEC10 at Edinburgh University.
POP-1 was developed by Robin Popplestone. POP-2 was designed by Rod Burstall and Robin Poppelstone in 1968 at Edinburgh as a highly interactive language system giving the user a total programming environment with an editor, compiler, debug facilities, etc and was used extensively by the AI Community. Programming in POP-2 gives some examples. Some of the features were:
POP-2 was initially implemented on the Elliott 4130 computer in the University.
Julian Davies implemented an extended version of POP-2, called POP-10 on the Edinburgh PDP-10 computer.
The major proposal by SIGAI was for the development of a new POP-2 system called WonderPop (sometimes WPOP). This was implemented by Robert Rae and Allan Ramsay under ICF support.
A major change in WPOP was from POP-2 involved putting objects of the same type and size in the same cage in the address space, and then all variable-sized objects (strings, vectors, functions, etc.) in a separate heap. The software worked very efficiently and incrementally compiled WonderPop ran as fast as compiled Pascal. WonderPop was under continuous development for over four years. There were also some compile-time syntactic typing (e.g. for integers and reals) as well as some pattern matching constructs for use with a variety of data-structures that were added.
Three dialects of LISP, the list processing language system, were maintained, all incompatible but each system had its adherents. Stanford LISP 1.6 was the smallest and used as a kernel for building larger systems. The CONNIVER system requires the MACLISP dialect. The Rutgers/UCI LISP was the cleanest and recommended for general use. The LISP-based symbolic algebra system was also supported by SIGAI.
The SIG staff also supported PROLOG, a language for programming in predicate calculus.
Most of the usage was from the AI Community in Edinburgh but users also came from Sussex, Warwick, London, Exeter, Liverpool and the London School of Economics (LSE).
Frank O'Gorman of Sussex University also implemented a version of POP2 on the ICL 1906A computer at Chilton.
When the Alvey Programme started in the UK in 1983, the SIG was reorganised and was funded by and reported to the Alvey IKBS Director. WonderPop was eventually superseded by POP-11 and then POPLOG.
Robin Popplestone died on 14 April 2004. Robert Rae has retired.
