Building Cocoa Applications: A Step by Step Guide

Working with the Terminal

In this section, we’ll cover the details of the Mac OS X Terminal application. Before getting into those details, though, we’ll take a step back to look briefly at the history of the video display terminal itself. That should give you some insight into why the Terminal application developed in the way it did.

History of the Video Display Terminal

Many years ago, long before personal computers were developed, computer systems were too big and too expensive to put on a single person’s desk. Instead, computers were put in special-purpose rooms (called “computer rooms”), where a staff of highly-trained professionals worked around the clock to keep the machines running. Many computer systems read their programs from decks of 80-column computer punch cards, each of which was punched with a series of holes that represented a single line of text. When a program was finished running the results were printed on a line printer. These systems were said to implement "batch mode processing” because programs were run in batches — there was no interactivity at all!

One of the first revolutions in computing was the development of interactive systems. In addition to being attached to a card reader and a line printer, the computer was equipped with a modified teletype printer. Every time a key on the teletype was pressed, a distinct code was sent to the computer. Every time the computer sent a code to the teletype, the teletype would literally print a letter onto a roll ...