There are many versions of Prolog available for PC, Macintosh and Unix systems, including versions for Microsoft Windows, to link Prolog to an Oracle relational database and for use with ‘object-oriented’ program design. These range from commercial systems with many features to public domain and ‘freeware’ versions. Some of these are listed (in alphabetical order) below, together with web addresses at which more information can be found.

• Amzi! Prolog
http://www.amzi.com/products/prolog_products.htm

• B-Prolog
http://www.probp.com/

• Ciao Prolog
http://clip.dia.fi.upm.es/Software/Ciao/

• GNU Prolog
http://gnu-prolog.inria.fr/

• Logic Programming Associates Prolog (versions for Windows, DOS and Macintosh)
http://www.lpa.co.uk

• Open Prolog (for Apple Macintosh)
http://www.cs.tcd.ie/open-prolog/

• PD Prolog (a public domain version for MS-DOS only)
http://www-2.cs.cmu.edu/afs/cs/project/ai-repository/ai/lang/prolog/impl/prolog/pdprolog/0.html

• SICStus Prolog
http://www.sics.se/isl/sicstuswww/site/index.html

• SWI Prolog
http://www.swi-prolog.org/

• Turbo Prolog (an old version that only runs in MS-DOS)
http://www.fraber.de/university/prolog/tprolog.html

• Visual Prolog
http://www.visual-prolog.com/

• W-Prolog (a Prolog-like language that runs in a web browser)
http://goanna.cs.rmit.edu.au/~winikoff/wp/

• YAP Prolog
http://www.ncc.up.pt/~vsc/Yap/