Notes: Friday 17 January 2002

Schedule

• Monday, 20 January: No Class - Martin Luther King Day (see below)
• Wednesday, 22 January: Problem Set 1
• Friday, 24 January: Read SICP, Section 1.2.
• Monday, 27 January: Read GEB, Little Harmonic Labyrinth and GEB, Chapter 5
• Monday, 3 February: Problem Set 2 (out Wednesday)

Notes and Questions

What is a formal system?

What is the difference between a formal system and a language?

Languages are made of:

• Primitives (almost all languages have these) - the simplest surface forms with meaning
• Means of Combination (all languages have these) - rules of production (ways to make new surface forms from ones you already have)
• Means of Abstraction (all powerful languages have these) - ways to use simple surface forms to represent complicated ones

When learning a foreign language, which of primitives, means of combination or means of abstraction is hardest to learn?

Who was Admiral Grace Hopper and what did she do?

Compiler: A program that translates between two languages, usually from a high-level programming language to machine code.

What is the difference between a compiler and an interpreter?

Why did John Backus want a precise way of describing languages?

Links

• ENIAC Story (like most ENIAC histories, it is wrong about ENIAC being the "world's first electronic digital computer" — we'll learn why before PS4)
• ENIAC Programmer's Manual
• USS Hopper
• Remembering Grace Murray Hopper: A Legend in Her Own Time, by Elizabeth Dickason.
• John Backus biography

Martin Luther King Links

• Martin Luther King, Jr. Papers Project at Stanford University
• Desegragation at UVa (including President Darden's letter)
• UVa's official short history
• Honor to the Class of '69 by Paul Gaston (describes Dr. King's March 1963 visit to UVa, four months before his "I Have a Dream" oration)

Questions

Why is Edgar Shannon the only past-president of UVa with nothing named after him?

How would President Shannon have handled the Pep Band incident?

Frankly, we didn't have the vaguest idea how the things would work out in detail... We struck out simply to optimze the object program, the running time, because most people at that time believed you really couldn't do that kind of thing.
John Backus (on FORTRAN language and compiler, quoted in 1966)

"When I use a word," Humpty Dumpty said, in a rather scornful tone, "it means just what I choose it to mean - nothing more nor less."
"The question is," said Alice, "whether you can make words mean so many different things."
"The question is," said Humpty Dumpty, "which is to be master that's all."
Through the Looking Glass — Chapter VI: Humpty Dumpty, Lewis Carroll

	CS 200: Computer Science Department of Computer Science University of Virginia	cs200-staff@cs.virginia.edu Using these Materials