Larry Breed

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This article is about Breed's relationship with APL. For more complete information about Breed, see Wikipedia.

Lawrence Moser Breed (July 17, 1940 - May 16, 2021[1]) was an implementor who worked on APL\360 and APL 1130, and cofounded STSC. There he developed the time-sharing system used by APL*PLUS, and Mailbox, one of the first ever email systems.

Breed studied at Stanford University as both an undergraduate and a graduate student, earning a B.S. in 1961 and a computer science M.S. in 1965. While an undergraduate, he created the first computer animation language and system, using it to coordinate a 100-foot display—an array of fans with colored cards—at Stanford football half-times.[2] After attending one of Ken Iverson's lectures in 1962, he informed Iverson of errors in the formal description (in Iverson notation) of IBM's System/360, and was hired to work alongside Iverson at IBM's Thomas J. Watson Research Center.[3] There he joined Phil Abrams, and the pair (supervised by Niklaus Wirth[4]) created the first APL implementation in 1965, running on an IBM 7090 mainframe.[5][6] They went on to create APL\1130[7] as well as APL\360. In 1973 the ACM awarded Breed, Dick Lathwell, and Roger Moore the Grace Murray Hopper Award from the "for their work in the design and implementation of APL\360, setting new standards in simplicity, efficiency, reliability and response time for interactive systems."[8]

In 1969 Breed co-founded STSC, where he led the development of the APL PLUS time-sharing system. While there, in 1972, he wrote Mailbox, one of the world's first worldwide email systems.[9]

Breed rejoined IBM in 1977. There he helped develop the APL standard ISO 8485:1989, and participated in non-APL projects including porting BSD onto IBM platforms, C compilers, and, floating-point arithmetic standards. He retired from IBM in 1992.



  1. Roger Hui. Larry Breed (1940-2021). Jsoftware general forum. 2021-05-19.
  2. Matthew Ward. "A (Spotty) History and Who's Who of Computer Graphics". Accessed 2021-05-29.
  3. Computer History Museum. "Larry Breed". Accessed 2021-05-29.
  4. An interpreter for Iverson notation
  5. Eugene McDonnell. The Socio-Technical Beginnings of APL.
  6. Adin Falkoff and Ken Iverson. "Design of APL" (pdf). IBM Journal of Research and Development. 17 (4): 324–334. Archived from the original on December 30, 2004.
  7. Larry Breed. How We Got To APL\1130. Vector journal vol. 22 no. 3. 2006-08.
  8. Association for Computing Machinery. 1993 Grace Murray Hopper Award. Accessed 2021-05-29.
  9. Roger Hui. APL and e-mail.

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