Path: utzoo!attcan!uunet!mcvax!ukc!eagle.ukc.ac.uk!icdoc!qmc-cs!don From: don@cs.qmc.ac.uk (Don Beal) Newsgroups: comp.lang.prolog Subject: BAe "DLM" Machine Message-ID: <729@sequent.cs.qmc.ac.uk> Date: 27 Sep 88 20:56:56 GMT Reply-To: don@cs.qmc.ac.uk (Don Beal) Organization: Computer Science Dept, Queen Mary College, University of London, UK. Lines: 47 Summary: Expires: Followup-To: Keywords: This article is being posted on behalf of Tony Pudner: -------- From A. Pudner, British Aerospace. Reference: "DLM - A powerful AI Computer for Embedded Expert Systems". Article in "Future Generation Computer Systems" Vol 3, No 4, Dec 87. The following consititute my reply to Richard O'Keefe's recent comments. 1) The above article describes 2 computers - an "Experimental DLM" and the "DLM-1". The "Experimental DLM" became operational during December 1986 and was designed only to test the DLM architecture. For this reason the memory areas were small and made from fast static RAM. The "DLM-1" was designed on the basis of the experience gained during the experimental phase. Unlike the experimental unit, the "DLM-1" is designed for "real" programs and has a sophisticated memory architecture. Richard's comments refer to the "Experimental DLM". However, it is the "DLM-1" that is the real machine and comments should be focussed in this direction. Briefly the parameters of the DLM-1 are: Memory speed: 100ns (DRAM) Memory working area: 9 Mbytes (upgradeable to 36 MB) Program memory size: 2 Mbytes Speed: 900 KLIPS (Deterministic concatenate) 2) The SUN-3 benchmarks (Quintus Prolog) are derived from the document "ALVEY PROLOG BENCHMARKS" by S.Dickens and A.Bustany. This document compares a number of Prolog benchmarks for different implementations and computers. The document is very useful, but is now 2 years old. If there are up-to-date figures for the SUN-4 and Quintus Prolog 2.4, I would be very interested to receive them. 3) The parameter (Prolog Speed * Memory Speed) is only useful for memory-bound computers. The DLM-1 is not memory bound, but for the record its "figure of merit" is 90 mLi. This compares with 7.5 mLi for the above SUN-3 implementation. 4) The benchmarks that I have done so far indicate that the DLM-1 is up to 100 times faster than the above SUN-3 implementation. The DLM-1 really comes into its own on non-deterministic programs. In fact, Naive Reverse, so far, gives the lowest performance ratio. 5) I am always interested in the opinions of other people on the DLM. Since I only came across Richard's comments by accident (BAe is not linked to usenet) I would be very grateful if any comments could be sent directly to me. My address is British Aerospace, Downshire Way, Bracknell, Berkshire, RG11 1QL, ENGLAND. Tel: +44 344 483222 Fax: +44 344 589000. Many thanks, Tony Pudner.