Rekursiv

Rekursiv was a computer processor designed by David M. Harland in the mid-1980s for Linn Smart Computing in Glasgow, Scotland. It was one of the few computer architectures intended to implement object-oriented concepts directly in hardware, a form of high-level language computer architecture. The Rekursiv operated directly on objects rather than bits, nibbles, bytes and words. Virtual memory was used as a persistent object store and unusually, the processor instruction set supported recursion (hence the name).

The project originated in an initiative within the hi-fi manufacturer Linn Products to improve its manufacturing automation systems, which at the time ran on a DEC VAX minicomputer. This resulted in the design of Lingo, an object-oriented programming language derived from Smalltalk and ALGOL. Due to the poor performance of Lingo on the VAX, a subsidiary company, Linn Smart Computing Ltd., was formed to develop a new processor to efficiently run Lingo.

The Rekursiv processor consisted of four gate-array chips named Numerik (32-bit ALU), Logik (instruction sequencer), Objekt (object-oriented memory management unit) and Klock (processor clock and support logic). A small number of prototype VMEbus boards, called Hades, comprising these four chips plus 80 MB of RAM were produced. These were intended for installation in a host system such as a Sun-3 workstation.

Although the Rekursiv was never fully developed and was not a commercial success, several Hades boards were used in academic research projects in the UK. The last known copy of a Rekursiv computer ended up at the bottom of the Forth and Clyde canal in Glasgow.

References

• The Jim Austin Computer Museum Rekursiv page
• The CPU Shack: Weird and Innovative Chips
• James Lothian (1993-03-15). "Re: Rekursiv chip (pretty long)". Newsgroup: comp.arch. Usenet: 33000@castle.ed.ac.uk.
• The Linn Rekursiv Story -REPOST

Further reading

• Harland, David M. (August 1988). Rekursiv: Object-Oriented Computer Architecture (Ellis Horwood Series in Computers and Their Applications). Ellis Horwood Ltd. ISBN 0-13-771965-5.
• Baines, Rupert (March 1990). "Taking RISCs". Personal Computer World. 13 (3): 136–140.
• Pountain, D. (1988). "Rekursiv: an object-oriented CPU". BYTE. 13 (12): 341–349.
• Harland, David M.; Gunn, Hamish I. E.; Pringle, Ian A.; Beloff, Bruno (September 1986). "The Rekursiv: An Architecture for Artificial Intelligence". Proc. AI Europa. {{cite conference}}: Unknown parameter |booktitle= ignored (|book-title= suggested) (help)
• Harland, David M.; Beloff, Bruno (December 1986). "Microcoding an Object-Oriented Instruction Set". ACM SIGARCH Computer Architecture News. 14 (5). Association for Computing Machinery: 3. doi:10.1145/18981.18982.
• Harland, David M.; Beloff, Bruno (April 1987). "Objekt: A Persistent Object Store with an Integrated Garbage Collector". ACM SIGPLAN Notices. 22 (4). Association for Computing Machinery: 70. doi:10.1145/24714.24723.
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