Amzi! Prolog + Logic Server - This extensible Prolog version runs under Windows, Linux, Solaris and HP/UX, supporting development of client and server applications embeddable in the web, C/C++, Java, Delphi, Visual Basic and other environments. An IDE is available for Windows along with an interpreter-based tutorial. Logic Programming Associates - WIN-PROLOG, DOS-PROLOG, MacProlog32 compilers. Products range from Prolog++ an OOPs extension, flex an expert system toolkit, and various web based technologies. [Commercial] SWI-Prolog - Stable and free standard Prolog implementation. Targeted primarily at research and education. Windows, Linux and Unix versions available. Comes with a visual debugger and a GUI environment. NU-Prolog - The successor of MU-Prolog, this compiled Prolog system designed and implemented in the mid-80's as a 'purer' logic solution, interfaces with UNIFY databases and is available under an academic license. IF/Prolog - A Prolog implementation for use in industrial and commercial environments. It complies with the ISO Prolog standard and runs on UNIX and MS-Windows environments. IF/Prolog has a rich set of interfaces to standard software components and an additional Constraint Technology Package for efficient solutions of complex optimization problems. Comes with a Java interface. Quintus Prolog - The Swedish Institute for Computer Science's implementation of Prolog for UNIX and PC platforms is embeddable, integrable and commercial-strength. Strawberry Prolog - This Prolog compiler for Windows 95/98/NT and Unix/Linux supports OLE and Prolog CGI Scripts. Strawberry Prolog is suitable for client-server applications and has unique debugging facilities. Logtalk - An object-oriented extension to the Prolog programming language. It integrates logic programming with object-oriented and event-driven programming. Compatible with most Prolog compilers. [Open source] Visual Prolog - A full-featured programming environment is offered with all the facilities necessary to write mission-critical, commercial-grade applications. A freeware version is available. INRIA wamcc - Predecessor to GNU Prolog. Compiles Prolog via GCC 2.x Qu-Prolog - The Software Verification Research Centre (Univ. of Queensland) extended version of Prolog currently released under Linux and Solaris is designed primarily as a prototyping language and tactic language for theorem provers, including support for efficient higher-order programming and logic programming of interactive applications. CU-Prolog - Constraint Unification Prolog (CUP) developed by the Institute for New Generation Computer Technology (ICOT), Japan. Originally written in C under Unix, MacCup is for Macintosh, DJCup for MS-DOS, with both implementations released as free software. CMU Free/Shareware Prolog - CMU's AI repository offers a collection of Prolog implementations. B-Prolog - Versatile and efficient CLP system based on Prolog with extensions for programming concurrency, constraints and interactive graphics. Runs on: Windows 9x/NT/2000/XP, Linux, Mac, Solaris, HP-UX, FreeBSD, SonyNews, Aix. Free evaluation version is available. Brain Aid Prolog - Based on Edinburgh Prolog and extended with object-oriented mechanisms, this Berkeley-style open-source system has a compiler written in Prolog and generates Transputer assembly code. ProFIT - Prolog with Features Inheritance, and Templates: Prolog extension with sorted feature structures (including multi-dimensional inheritance), finite domains, feature search, cyclic terms, templates. GNU Prolog - This compiler accepts Prolog + constraint programs and produces native binaries. The obtained executable is subsequently stand-alone. The size of this executable can be quite small since GNU Prolog can avoid linking the code of most unused built-in predicates. The performance of GNU Prolog is very encouraging (comparable to commercial systems). Aquarius Prolog 1.0 - The compiler for this open-source version developed at UCB is built around the Berkeley Abstract Machine, a finer-grained rendition of WAM. An interpreter provided for program development is written in Prolog. K-Prolog - This is the English download site for this Japanese implementation of Prolog for Solaris, HP-UX, Digital UNIX, Linux and 32-bit Windows environments. The YAP Prolog System - The University of Porto's Edinburgh-style, WAM-based Prolog engine is available on 32-bit machines running Sun and Linux and 64-bit Alphas running OSF UNIX and Linux. An open-source policy is being implemented with regard to distribution. Reform Prolog - Recursion-parallel Single Program, Multiple Data (SPMD) implementation; assumes one sequential worker and arbitrary, fixed number parallel workers, each worker is process, can have more workers than processors. Successor: High Performance Erlang. [Open Source, GPL] Jekejeke Prolog - Jekejeke Prolog is an interpreter only implementation of Prolog written in 100% Java. The runtime library provides a simple console interface and no debugger. The development environment also provides a debugger. The implementation of the language mainly follows the ISO Prolog core standard. The implementation also features an application programming interface. The Ciao System - General-purpose programming language which supports logic, constraint, functional, higher-order and object-oriented programming styles. Its main design objectives are high expressive power, extensibility, safety, reliability and efficient execution. [Open Source, GPL] SICStus Prolog 3 - This ISO-conformant, performance-oriented Prolog development system also features interfaces with C/C++, Java and ODBC-compliant DBMS's and an OOP extension.