Logic programming is ideally suited for knowledge processing. The aim being development of computers capable of human like reasoning, it forms the heart of such machines. Hence these is a need for efficient hardware support for logic programming languages in order to perform fast knowledge processing,. Various architectures based on the three models of computations, namely, conventional control flow, novel dataflow and reduction, have been proposed. The dataflow model promises to be one of the most interesting ones because of it capability to exploit fine grain parallelism. The VLSI technology revolution has given a fillip to consider dataflow architectures as a viable proposition to build parallel logic machines. In this paper, we discuss the various issues of logic programming from an implementation point of view and review three dataflow architectures that have been proposed for executing logic programs.