Assignment

History of computers

This chapter is a brief summary of the history of Computers. It is supplemented by the two PBS

documentaries video tapes "Inventing the Future" And "The Paperback Computer". The chapter

highlights some of the advances to look for in the documentaries.

In particular, when viewing the movies you should look for two things:

 The progression in hardware representation of a bit of data:

1. Vacuum Tubes (1950s) - one bit on the size of a thumb;

2. Transistors (1950s and 1960s) - one bit on the size of a fingernail;

3. Integrated Circuits (1960s and 70s) - thousands of bits on the size of a hand

4. Silicon computer chips (1970s and on) - millions of bits on the size of a finger

nail.

 The progression of the ease of use of computers:

1. Almost impossible to use except by very patient geniuses (1950s);

2. Programmable by highly trained people only (1960s and 1970s);

3. Useable by just about anyone (1980s and on).

to see how computers got smaller, cheaper, and easier to use.

The first substantial computer was the giant

ENIAC machine by John W. Mauchly and J.

Presper Eckert at the University of Pennsylvania.

ENIAC (Electrical Numerical Integrator and

Calculator) used a word of 10 decimal digits

instead of binary ones like previous automated

calculators/computers. ENIAC was also the first

machine to use more than 2,000 vacuum tubes,

using nearly 18,000 vacuum tubes. Storage of all

those vacuum tubes and the machinery required

to keep the cool took up over 167 square meters (1800 square feet) of floor space. Nonetheless, it

had punched-card input and output and arithmetically had 1 multiplier, 1 divider-square rooter,

and 20 adders employing decimal "ring counters," which served as adders and also as quick-

access (0.0002 seconds) read-write register storage.

The executable instructions composing a program were embodied in the separate units of

ENIAC, which were plugged together to form a route through the machine for the flow of

computations. These connections had to be redone for each different problem, together with

presetting function tables and switches. This "wire-your-own" instruction technique was

inconvenient, and only with some license could ENIAC be considered programmable; it was,

however, efficient in handling the particular programs for which it had been designed. ENIAC is

generally acknowledged to be the first successful high-speed electronic digital computer (EDC)

and was productively used from 1946 to 1955. A controversy developed in 1971, however, over
the patentability of ENIAC's basic digital concepts, the claim being made that another U.S.

physicist, John V. Atanasoff, had already used the same ideas in a simpler vacuum-tube device

he built in the 1930s while at Iowa State College. In 1973, the court found in favor of the

company using Atanasoff claim and Atanasoff received the acclaim he rightly deserved.

Progression Hardware

In the 1950's two devices would be invented that would improve the computer field and set in

motion the beginning of the computer revolution. The first of these two devices was the

transistor. Invented in 1947 by William Shockley, John Bardeen, and Walter Brattain of Bell

Labs, the transistor was fated to oust the days of vacuum tubes in computers, radios, and other

electronics.

The vacuum tube, used up to this time in almost all the

computers and calculating machines, had been invented by

American physicist Lee De Forest in 1906. The vacuum tube,

which is about the size of a human thumb, worked by using

large amounts of electricity to heat a filament inside the tube

until it was cherry red. One result of heating this filament up

was the release of electrons into the tube, which could be

controlled by other elements within the tube. De Forest's original device was a triode, which

could control the flow of electrons to a positively charged plate inside the tube. A zero could

then be represented by the absence of an electron current to the plate; the presence of a small but

detectable current to the plate represented a one.

deal of space, and needed to be replaced often. Computers

of the 1940s and 50s had 18,000 tubes in them and

housing all these tubes and cooling the rooms from the

heat produced by 18,000 tubes was not cheap. The

transistor promised to solve all of these problems and it

did so. Transistors, however, had their problems too. The

main problem was that transistors, like other electronic

components, needed to be soldered together. As a result, the more complex the circuits became,

the more complicated and numerous the connections between the individual transistors and the

likelihood of faulty wiring increased.

Mainframes to PCs

The 1960s saw large mainframe computers become much more common in large industries and

with the US military and space program. IBM became the unquestioned market leader in selling

these large, expensive, error-prone, and very hard to use machines.

A veritable explosion of personal computers occurred in the early 1970s, starting with Steve Jobs

and Steve Wozniak exhibiting the first Apple II at the First West Coast Computer Faire in San

Francisco. The Apple II boasted built-in BASIC programming language, color graphics, and a

4100 character memory for only $1298. Programs and data could be stored on an everyday

audio-cassette recorder. Before the end of the fair, Wozniak and Jobs had secured 300 orders for

the Apple II and from there Apple just took off.

Radio Shack. In its second incarnation, the TRS-80 Model II, came complete with a 64,000

character memory and a disk drive to store programs and data on. At this time, only Apple and

TRS had machines with disk drives. With the introduction of the disk drive, personal computer

applications took off as a floppy disk was a most convenient publishing medium for distribution

of software.

IBM, which up to this time had been producing mainframes and minicomputers for medium to

large-sized businesses, decided that it had to get into the act and started working on the Acorn,

which would later be called the IBM PC. The PC was the first computer designed for the home

market which would feature modular design so that pieces could easily be added to the

architecture. Most of the components, surprisingly, came from outside of IBM, since building it

with IBM parts would have cost too much for the home computer market. When it was

introduced, the PC came with a 16,000 character memory, keyboard from an IBM electric

typewriter, and a connection for tape cassette player for $1265.

By 1984, Apple and IBM had come out with new models. Apple released the first generation

Macintosh, which was the first computer to come with a graphical user interface (GUI) and a

mouse. The GUI made the machine much more attractive to home computer users because it was

easy to use. Sales of the Macintosh soared like nothing ever seen before. IBM was hot on Apple's

tail and released the 286-AT, which with applications like Lotus 1-2-3, a spreadsheet, and

Microsoft Word, quickly became the favorite of business concerns.

That brings us up to about ten years ago. Now people have their own personal graphics

workstations and powerful home computers. The average computer a person might have in their
home is more powerful by several orders of magnitude than a machine like ENIAC. The

computer revolution has been the fastest growing technology in man's history.

Reference

http://homepage.cs.uri.edu/faculty/wolfe/book/Readings/Reading03.htm