Cursos2007: enero 2008

Lenguajes de Programación. 4a. Sesión 2007-08-16

History[1]:

The first true general- purpose electronic computer was the ENIAC, which was constructed at the University of Pennsylvania between 1943 and 1946. However, ENIAC's underlying architecture was very different to that of modern computers. “When it was first built it could not store programs. Each new computation required moving plugs and jumper cables”[2]. During the course of designing ENIAC, it's creators, John William Mauchly and J. Presper Eckert Jr., conceived the concept of stored program computing.

This concept was subsequently documented by Johann (John) von Neumann in his paper which is now known as the “First Draft of a reporte to the EDVAC” ( June, 1945). The computer structure resulting from the criteria presented in the "First Draft" is popularly known as a von Neumann Machine, and virtually all digital computers from that time forward have been based on this architecture.)

The basic elements of a stored program computer (von Neumann Machine’s architecture) are:

1. A memory containing both data and instructions. Also to allow both data and instruction memory locations to be read from, and written to, in any desired order. The memory storages information coded in Binary Code (1’s and 0’s)

2. A calculating unit (ALU) capable of performing both arithmetic and logical operations on the data. It contains special registers ( Accumulators = Acc)

3. A control unit, which could interpret an instruction retrieved from the memory and select alternative courses of action based on the results of previous operations.