Editing Lisp machine (section)

===Commercializing MIT Lisp machine technology===
{{original research|section|date=June 2021}}
[[File:Lisp machines in Computer History Museum.jpg|thumb|Symbolics 3620 (left) and LMI Lambda Lisp machines]]
In 1979, [[Russell Noftsker]], being convinced that Lisp machines had a bright commercial future due to the strength of the Lisp language and the enabling factor of hardware acceleration, proposed to Greenblatt that they commercialize the technology.{{Citation needed|date= October 2009}} In a counter-intuitive move for an AI Lab hacker, Greenblatt acquiesced, hoping perhaps that he could recreate the informal and productive atmosphere of the Lab in a real business. These ideas and goals were considerably different from those of Noftsker. The two negotiated at length, but neither would compromise. As the proposed firm could succeed only with the full and undivided assistance of the AI Lab hackers as a group, Noftsker and Greenblatt decided that the fate of the enterprise was up to them, and so the choice should be left to the hackers.

The ensuing discussions of the choice divided the lab into two factions. In February 1979, matters came to a head. The hackers sided with Noftsker, believing that a commercial venture-fund-backed firm had a better chance of surviving and commercializing Lisp machines than Greenblatt's proposed self-sustaining start-up. Greenblatt lost the battle.

It was at this juncture that [[Symbolics]], Noftsker's enterprise, slowly came together. While Noftsker was paying his staff a salary, he had no building or any equipment for the hackers to work on. He bargained with [[Patrick Winston]] that, in exchange for allowing Symbolics' staff to keep working out of MIT, Symbolics would let MIT use internally and freely all the software Symbolics developed. A consultant from [[Control Data Corporation|CDC]], who was trying to put together a natural language computer application with a group of West-coast programmers, came to Greenblatt, seeking a Lisp machine for his group to work with, about eight months after the disastrous conference with Noftsker. Greenblatt had decided to start his own rival Lisp machine firm, but he had done nothing. The consultant, Alexander Jacobson, decided that the only way Greenblatt was going to start the firm and build the Lisp machines that Jacobson desperately needed was if Jacobson pushed and otherwise helped Greenblatt launch the firm. Jacobson pulled together business plans, a board, a partner for Greenblatt (one F. Stephen Wyle). The newfound firm was named ''LISP Machine, Inc.'' (LMI), and was funded by CDC orders, via Jacobson.

Around this time Symbolics (Noftsker's firm) began operating. It had been hindered by Noftsker's promise to give Greenblatt a year's [[Head start (positioning)|head start]], and by severe delays in procuring venture capital. Symbolics still had the major advantage that while 3 or 4 of the AI Lab hackers had gone to work for Greenblatt, 14 other hackers had signed onto Symbolics. Two AI Lab people were not hired by either: [[Richard Stallman]] and [[Marvin Minsky]]. Stallman, however, blamed Symbolics for the decline of the hacker community that had centered around the AI lab. For two years, from 1982 to the end of 1983, Stallman worked by himself to clone the output of the Symbolics programmers, with the aim of preventing them from gaining a monopoly on the lab's computers.<ref>Levy, S: ''Hackers''. Penguin USA, 1984</ref>

Regardless, after a series of internal battles, Symbolics did get off the ground in 1980/1981, selling the CADR as the LM-2, while [[Lisp Machines]], Inc. sold it as the LMI-CADR. Symbolics did not intend to produce many LM-2s, since the 3600 family of Lisp machines was supposed to ship quickly, but the 3600s were repeatedly delayed, and Symbolics ended up producing ~100 LM-2s, each of which sold for $70,000. Both firms developed second-generation products based on the CADR: the [[Symbolics]] 3600 and the LMI-LAMBDA (of which LMI managed to sell ~200). The 3600, which shipped a year late, expanded on the CADR by widening the machine word to 36-bits, expanding the address space to 28-bits,<ref>Moon 1985</ref> and adding hardware to accelerate certain common functions that were implemented in microcode on the CADR. The LMI-LAMBDA, which came out a year after the 3600, in 1983, was compatible with the CADR (it could run CADR microcode), but hardware differences existed. [[Texas Instruments]] (TI) joined the fray when it licensed the LMI-LAMBDA design and produced its own variant, the [[TI Explorer]]. Some of the LMI-LAMBDAs and the TI Explorer were dual systems with both a Lisp and a [[Unix]] processor. TI also developed a 32-bit [[microprocessor]] version of its Lisp CPU for the TI Explorer. This Lisp chip also was used for the MicroExplorer – a [[NuBus]] board for the Apple [[Macintosh II]] (NuBus was initially developed at MIT for use in Lisp machines).

Symbolics continued to develop the 3600 family and its operating system, [[Genera (operating system)|Genera]], and produced the Ivory, a [[very-large-scale integration|VLSI]] implementation of the Symbolics architecture. Starting in 1987, several machines based on the Ivory processor were developed: boards for Suns and Macs, stand-alone workstations and even embedded systems (I-Machine Custom LSI, 32 bit address, Symbolics XL-400, UX-400, MacIvory II; in 1989 available platforms were Symbolics XL-1200, MacIvory III, UX-1200, Zora, NXP1000 "pizza box"). Texas Instruments shrank the Explorer into silicon as the MicroExplorer which was offered as a card for the Apple [[Mac II]]. LMI abandoned the CADR architecture and developed its own K-Machine,<ref name= "K-Machine">{{citation |url= http://home.comcast.net/%7Eprunesquallor/kmachine.htm |title= K-Machine}}</ref> but LMI went bankrupt before the machine could be brought to market. Before its demise, LMI was working on a distributed system for the LAMBDA using Moby space.<ref>[http://www.patentgenius.com/patent/4779191.html Moby space] {{Webarchive|url=https://web.archive.org/web/20120225075453/http://www.patentgenius.com/patent/4779191.html |date=25 February 2012 }} Patent application 4779191</ref>

These machines had hardware support for various primitive Lisp operations (data type testing, [[CDR coding]]) and also hardware support for incremental [[garbage collection (computer science)|garbage collection]]. They ran large Lisp programs very efficiently. The Symbolics machine was competitive against many commercial super [[minicomputer]]s, but was never adapted for conventional purposes. The Symbolics Lisp Machines were also sold to some non-AI markets like [[computer graphics]], modeling, and animation.

The MIT-derived Lisp machines ran a Lisp dialect named [[Lisp Machine Lisp]], descended from MIT's [[Maclisp]]. The operating systems were written from the ground up in Lisp, often using object-oriented extensions. Later, these Lisp machines also supported various versions of [[Common Lisp]] (with [[Flavors (programming language)|Flavors]], [[New Flavors]], and [[Common Lisp Object System]] (CLOS)).