The parallel logic programming system in the FGCS project and its future directions

Abstract In the fifth generation computer systems (FGCS) project, a parallel logic programming language, KL1, was adopted as the project's kernel language. It was not only used to determine architectures of highly parallel machines called parallel inference machines (PIMs) consisting of about 1000 element processors but also used as a system description language to develop basic software such as a parallel operating system (PIMOS), and symbolic processing and knowledge processing application systems such as knowledge description languages, a parallel theorem prover, and a protein sequence analysis program. It achieved great success in exploiting of parallelism involved in several important application systems. The prototype of the FGCS attained a linear speed-up that was proportional to the number of processing elements (PEs) for the application systems we had targeted. The MGTP parallel theorem prover was one of such application systems, and can prove theorems based on full first-order logic. Thus, it indicates the possibility of designing a new practical knowledge representation language whose expressive power will be much greater than that of conventional ones. In the FGCS follow-on project, KL1 and its programming system were ported to Unix-based stock parallel machines. This new system called KLIC is expected to greatly extend the use of highly parallel systems.