From X Mon Mar 15 16:22:57 CST 1993 Article: 36365 of alt.folklore.computers Xref: uchinews alt.folklore.computers:36365 comp.arch:23047 Path: uchinews!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!wupost!uunet!pipex!warwick!uknet!edcastle!castle.ed.ac.uk!jlothian From: jlothian@castle.ed.ac.uk (J Lothian) Newsgroups: alt.folklore.computers,comp.arch Subject: Re: Rekursiv chip (pretty long) Message-ID: <33000@castle.ed.ac.uk> Date: 15 Mar 93 21:40:58 GMT References: <1nlrvq$77f@armory.centerline.com> <1993Mar <1993Mar12.154050.12094@exlog.com> <5770@blue.cis.pitt.edu> Sender: nntpusr@castle.ed.ac.uk Organization: Edinburgh University Computing Service Lines: 103 Status: RO In article <5770@blue.cis.pitt.edu>, wbdst+@pitt.edu (William B Dwinnell) writes: |> |> Does anyone know what happened to the Rekursiv chip, which was |> a microprocessor built in the UK? I think there was a write-up |> on it in "Byte" a couple years ago. [I'm crossposting this to comp.arch, since it seems relevant.] Welll... It's an interesting and somewhat long story. The upshot of it is that (a) the company building the machine failed to get a patent on it in Japan, (b) by the time the machine had gone from lab prototype to marketable board, the 486, Sparc &c had come along and the rekursiv was more or less obsolete as a consequence, (c) Linn (the company building it, who normally make expensive hi-fi) were in financial difficulties, and couldn't really afford the project, (d) nobody at Linn understood the machine, or had the foggiest idea how to market it, or who to market it to, (e) the Linn van driver drove the Linn van into the side of David Harland's (principal Rekursiv architect) Porsche and Linn wouldn't pay for the repairs, which was the last straw as far as David was concerned, and he stopped coming in to work, and (f) Linn then shut the project down. They said at the time that they were putting it into a state of 'hibernation', but I think that it's a fair bet you won't see it again. The name of one of the Rekursiv chips was subsequently re-cycled by Linn as the name of the decoder for their new CD player ('Numerik' was originally the Rekursiv's ALU chip). The full chipset was Numerik (ALU), Logik (sequencer), Objekt (object- oriented MMU) and Klock (various timers &c). It's a great shame. In retrospect, though, it's easy to see that the project was seriously out of touch with reality: the Rekursiv was designed in the days when Vaxes ruled the roost; by the time the design had been condensed down to the 4 monster gate-arrays, hefty PCs and Sparcstations &c had started to appear, and the machine just couldn't hold its own. It could only really have succeeded if it had been backed by one of the really big computer manufacturers, who could have made the investment required to keep it ahead of the competition. It was a really interesting and unusual design: the main memory was in effect a persistent object store, with every object having its type, size and position in memory known in hardware, so that (for example) the hardware could prevent you from 'running off' the end of an array and corrupting surrounding memory. Paging of objects into and out of main memory was handled by the host machine (generally a Sun 3), and was completely transparent, even at the microcode level. This meant that you could write arbitrarily complex algorithms in microcode, even recursive ones, hence the machine's name. Every object had a unique identifier (a 40-bit number), and the MMU chip would translate that into the object's store address (if it was in main memory). Since only the MMU knew the object's address, an object could be moved around in memory without having to update references to it (since they were in terms of its object number); this made garbage-collection particularly straightforward. The support software (microsimulator and so forth) was written to run under X10, and wasn't well enough behaved to run with the X10/X11 protocol converter that went the rounds for a while, so they were well and truly stuffed when X11 started to gain serious acceptance (particularly given that the X10 that we had wouldn't run under sunos 4.*). I'm not sure what happened to the people on the project after it was shut down. One of them (Brian Drummond) stayed on at Linn to provide a certain amount of support for Rekursiv users (about 30 machines were sold) and to try his hand at loudspeaker design. Ian Ellsley was last heard of in China, swearing he'd never touch another Sun again. Bruno Beloff worked for Oracle in Chertsey for about 2 weeks, before deciding that Surrey didn't suit him and going to South Africa to take photographs of riots. Duncan McIntyre was apparently heading for France. David Harland is rumoured to be alive and well, but working on something much more ambitious :-). I spent two and a half truly ghastly years cooped up in a poky little office* in Edinburgh University's amazingly unfriendly Computer Science department, microcoding a Prolog instruction set for the Rekursiv, being yelled at for no apparent reason by other members of staff, and generally having a thoroughly miserable time, which makes it all the more bizarre that I look back on the project with a certain amount of affection even now. I still have a T-shirt (daft promotional effort) with 'Rekursiv' written across the front in large colourful letters. I think they only made about 20 or something; maybe it'll be valuable some day. More to the point, I also have a full set of chip databooks & software manuals &c. I have a QIC tape somewhere that may or may not have a Rekursiv software release on it. There is apparently a PC version of Lingo (the Rekursiv's principal language, very like Smalltalk), but you'd have to ask Linn about that. James (rekursiv project survivor) -- *actually, several offices: from time to time, someone would come to my office and say 'Right, you're moving offices. Now.' and I would just have to drop whatever I was doing and go. They never gave you any notice, or for that matter any reason. I got the impression that they did this just to foster a degree of paranoia among the staff. Definitely a place to avoid. ------------------------------------------------------- James Lothian | "It's life, Jim, james@uk.ac.ed.caad | but not as we know it"