Church, Turing and von Neuman

Alonzo Church solved the halting problem with the invention of lambda calculus. Alan Turing solved the equivanent problem by the invention of the Turning machine. John Von Neuman proposed an electronic computer based on the Universal Turing Machine to do physics calculation for nuclear fusion evaluation, his model is the basis for our modern computer systems.

FORTRAN and LISP

The first high level compiled language was FORTRAN. First proposed in 1953 the first compiler was delivered in 1957. In 1958 John McCarthy proposed a language LISP which concerned ideas of Church’s lambda calculus. The first compiler was implmented in 1959, during 1962 the first ocmpiler of LISP written completely in LISP was delivered. This was an incremental compiler which piece by piece compiled itself. This began the tradition of the interactive REPL that is part of today’s LISP system, as a consequence the concept of the IMAGE of a LISP system was also developed.

My Model for a computer

This is my rough description of the von Neuman architecture.

  • An Input Device or Stream
  • A CPU with control, math and logic units
  • A Memory unit
  • An Output Device or Stream

How a LISP REPL maps to the computer

  • Input is READ
  • The read form is evaluated by the CPU
  • Changes in the LISP Image are memory
  • The Output is PRINTED