Lesson plan

FOCAL (programming language)

FOCAL (acronym for Formulating On-line Calculations in Algebraic Language, or FOrmula CALculator ) is an interactive interpreted programming language based on JOSS and mostly used on Digital Equipment Corporation (DEC) PDP series machines. JOSS was designed to be an interactive language to allow programs to be easily written by non-programmers. FOCAL is very similar to JOSS in the commands it supports and the general syntax of the language. It differs in that many of JOSS' advanced features like ranges and user-defined functions were removed to simplify the parser and allow the system to run in less memory. Some of the reserved words (keywords) were renamed so that they all start with a unique first letter. This allows users to type in programs using one-character statements, further reducing memory needs. This was an important consideration on the PDP-8, which was often limited to a few kilobytes (KB). Like JOSS, and later BASICs, FOCAL on the PDP-8 was a complete environment that included a line editor, an interpreter, and input/output routines. The package as a whole was named FOCAL-8, which also ran on the PDP-5 and PDP-12. When ported to the PDP-11, the resulting FOCAL-11 relied on the underlying operating system, RT-11, to provide file support and editing. The language definition was updated twice, to FOCAL-69 and a very slightly modified FOCAL-71.…

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Article summary

FOCAL (acronym for Formulating On-line Calculations in Algebraic Language, or FOrmula CALculator ) is an interactive interpreted programming language based on JOSS and mostly used on Digital Equipment Corporation (DEC) PDP series machines. JOSS was designed to be an interactive language to allow programs to be easily written by non-programmers. FOCAL is very similar to JOSS in the commands it supports and the general syntax of the language. It differs in that many of JOSS' advanced features like ranges and user-defined functions were removed to simplify the parser and allow the system to run in less memory. Some of the reserved words (keywords) were renamed so that they all start with a unique first letter. This allows users to type in programs using one-character statements, further reducing memory needs. This was an important consideration on the PDP-8, which was often limited to a few kilobytes (KB). Like JOSS, and later BASICs, FOCAL on the PDP-8 was a complete environment that included a line editor, an interpreter, and input/output routines. The package as a whole was named FOCAL-8, which also ran on the PDP-5 and PDP-12. When ported to the PDP-11, the resulting FOCAL-11 relied on the underlying operating system, RT-11, to provide file support and editing. The language definition was updated twice, to FOCAL-69 and a very slightly modified FOCAL-71.…

Key claims

  1. release date: 1968 — source: Wikipedia · confidence 0.95
  2. release date: 1985 — source: Wikipedia · confidence 0.95
  3. release date: 1969 — source: Wikipedia · confidence 0.95

Discussion questions

  1. Summarise the article in your own words. Which single claim would you verify first, and why?
  2. The record states that the release date is "1968". What evidence would count against this claim?
  3. The record states that the release date is "1985". What evidence would count against this claim?
  4. The record states that the release date is "1969". What evidence would count against this claim?
  5. Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
  6. If two sources disagreed about one of these facts, what would you need in order to trust one over the other?

Bibliography

  1. Wikipedia https://en.wikipedia.org/w/index.php?oldid=1358706125

Key claims and bibliography are generated from the same tracked claims and sources as the article page.