The Howdy Glossary

Parlog is a programming language designed for parallel systems, combining "parallel" and "Prolog" to emphasize its purpose. Created by David May at the Inmos Transputer Applications Research Group in the 1980s, Parlog was tailored for transputer-based machines and aimed to leverage their parallel processing capabilities efficiently. It allowed developers to express applications through concurrent processes that communicate via message passing, making it ideal for distributed systems. Despite these advantages, its adoption remained limited primarily due to the decline of interest in transputers during the late 1980s and 1990s.

During its peak period in the 1980s and 1990s, Parlog competed with other parallel programming languages like Occam, Erlang, and CSP. Each of these languages offered unique approaches to handling concurrency and communication challenges inherent in distributed systems. While competitors provided distinct concurrency models or communication mechanisms tailored to specific developer needs in parallel computing domains, Parlog's distinguishing feature was its integration of logic programming principles from Prolog with robust parallel processing capabilities. This combination provided a unique angle for expressing applications meant for distributed systems through concurrent processes communicating via message passing.

A significant advantage of Parlog lies in seamlessly merging logical reasoning with efficient parallelism rooted in Prolog's foundations. This capability allows developers to design applications for parallel systems concisely while maintaining logical structure—a crucial aspect when handling multiple processes simultaneously within distributed environments. Thus, despite limited widespread use beyond educational settings and research projects focused on exploring parallelism, Parlog remains notable as a specialized tool offering effective solutions for complex issues within parallel computing domains where both logic-based reasoning and efficient process management are essential attributes.