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Digital Equipment Corp. FOCAL language manuals and information
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DEC-FOCAL-Manuals-and-Info/abstract.txt

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  1. 

  2. FOCAL (acronym for Formulating On-line Calculations in Algebraic Language, 

  3. or FOrmula CALculator) is an interactive interpreted programming 

  4. language based on JOHNNIAC Open Shop System (JOSS) and mostly used on 

  5. Digital Equipment Corporation (DEC) Programmed Data Processor (PDP) 

  6. series machines.

  7. 

  8. FOCAL (acronym for Formulating On-line Calculations in Algebraic Language,

  9.  or FOrmula CALculator) is an interactive interpreted programming language 

  10. based on JOHNNIAC Open Shop System (JOSS) and mostly used on Digital 

  11. Equipment Corporation (DEC) Programmed Data Processor (PDP) series 

  12. machines. FOCAL is very similar to JOSS in the commands it supports 

  13. and the general syntax of the language. It differs in that many of 

  14. JOSS' advanced features like ranges and user-defined functions were 

  15. removed to simplify the parser. Some of the reserved words (keywords) 

  16. were renamed so that they all start with a unique first letter. 

  17. This allows users to type in programs using one-character statements, 

  18. further reducing memory needs. This was an important consideration 

  19. on the PDP-8, which was often limited to a few kilobytes (KB). 

  20. Like JOSS, and later BASICs, FOCAL on the PDP-8 was a complete 

  21. environment that included a line editor, an interpreter, and 

  22. input/output routines. The package as a whole was named FOCAL-8, 

  23. which also ran on the PDP-5 and PDP-12. When ported to the PDP-11, 

  24. the resulting FOCAL-11 relied on the underlying operating system, 

  25. RT-11, to provide file support and editing. The language definition 

  26. was updated twice, to FOCAL-69 and a very slightly modified FOCAL-71. 

  27. A port to the Intel 8080 was also available. FOCAL is notable as the 

  28. language in which the original versions of the early video games 

  29. Hamurabi and Lunar Lander were written. Both were later ported to 

  30. BASIC, where they became much better known. FOCAL was not popular 

  31. outside the PDP platform and largely disappeared during the move to 

  32. the VAX-11. It had a strong revival in the Soviet Union where PDP-11 

  33. clones were used as educational and home computers. (en)

  34. 

  35. 

  36. Developer: Richard_Merrill_(computer_scientist)

  37. Influenced: BASIC-Plus

  38. 

  39. 

  40. Richard Merrill was a Digital Equipment Corporation employee who 

  41. invented the FOCAL programming language and programmed the first 

  42. two interpreters for the language in 1968 and 1969, for the PDP-8. 

  43. He also developed later versions of the interpreter for the PDP-7 

  44. and PDP-9, later ported it to the PDP-11. Merrill also designed 

  45. and programmed the EDIT-8 text editor (using paper-tape). Rick Merrill 

  46. is an alumnus of Episcopal High School, a preparatory school in 

  47. Alexandria, VA and of M.I.T BS'63 MS'65 and Clark University MBA'85 (en)

  48. 

  49.