The Modern Computer

All the types of computers we have been studying are machines that are both electronic and digital. By electronic we mean a machine that uses components such as vacuum tubes, transistors, or silicon chips. All these electronic devices require electricity. By digital we mean a computer that uses the binary arithmetic system as the basis for its operation. Binary arithmetic uses only two digits: the 0 and the 1. Thus the electronic digital computer is generally considered the modern computer, which dates from the early 1940s.

The Analog Computer

In contrast to the digital computer, there is also an analog computer. Analog means the computer does not count in two digits, but rather continuously measures and compares changing values. One example is a computerized thermostat, which regulates the heat or air conditioning in a building. An analog radio tuner has a needle or arm that moves from station to station when you turn the knob; a digital radio tuner displays the precise frequency when you touch a button. Analog computers are in wide use, but rarely for the same purposes as digital computers. However, there are important differences between the two in the types of work they perform.

Knowledge Check:

1. What is the other term used to describe a personal

computer?

2. Name several different types of personal computers.

3. What are the three components of every computer?

4. How is the minicomputer different from the mainframe

computer?

5. How is the role of the mainframe changing?

6. What are the primary uses for the supercomputer?

7. What are the two characteristics of the modern

computer?

8. What is a common example of an analog computer?

How Computers Do Their Work

In the definition of a computer, we learned that the computer accepts data. The term data is defined as facts and numbers suitable for communication or interpretation. Strictly speaking, a single unit of data is termed a datum; data is the plural term. When people or a computer act on that data, we call it processing. Data processing is the computer system using specific procedures that turn data into useful information for people. Data is the raw material of information. People turn the data computers produce into useful information through understanding, integrating, and applying them to our world.

Yesterday eniac – The First Electronic Digital Computer

In 1937, the League of Nations commissioned the world's best minds to forecast future technologies. When these experts submitted their report, there was no mention of a computer. Yet ever as they convened, John Atanasoff, a physics professor at Iowa State University, was at work on the first computer.

Many of his ideas would find their way into ENIAC, the Electronic Numerical Integrator and Calculator. ENIAC was a project commissioned by the U.S. Army's Ordnance Department, which was seeking a better way to plot ballistics trajectories. John Mauchly and J. Presper Eckert headed up the project, which got underway in 1943 at the University of Pennsylvania. Some of the best academics in the country worked on ENIAC.

When it was completed in1946, at a cost of $3 million, it stood two stories high, weighed 30 tons, and covered an area the size of two football fields. Its electronic circuitry was comprised of 18,000 vacuum tubes, 70,000 resistors, 10,000 capacitors, and 6,000 switches that made up 100,000 circuits. When ENIAC was turned on, it was said, the lights of Philadelphia dimmed. Yet ENIAC was not much more complicated than a modern hand-held calculator, and was only able to perform a mathematical computation about as fast.

Unfortunately for ENIAC, World War II ended in 1945; thus it was unable to fulfill its original purpose. However, ENIAC was put to work on calculations for atomic bomb research at the Los Alamos, New Mexico, government research laboratories. Today, some portions of ENIAC are on display in the Smithsonian Institution in Washington, D.C.

ENIAC was a research computer, but its descendant, UNIVAC, was designed for commercial purposes by Mauchly and Eckert. They formed their own computer company to build UNIVAC, the Universal Automatic Computer, but they were not good businessmen and eventually had to sell their interests to Remington Rand. The UNIVAC I was introduced in 1951, and the U.S. Bureau of the Census received the first one to tabulate census statistics. The government also bought two more. Shortly thereafter, a computer made its first television appearance. UNIVAC was used to predict the 1952 presidential election—and it did a good job, forecasting that Dwight Eisenhower would win 438 electoral votes to Adlai Stevenson's 93. The actual count was 442 to 89.

The next year, General Electric became the first private business to buy a computer. Then other businesses began clamoring for UNIVACs, which were sold in rapid succession to Metropolitan Life Insurance, U.S. Steel, Du Pont, and Franklin Life.

The problem or task must be presented in a very specific and precise manner. If it is not, the computer won't be able to help.

People can make the computer do many sophisticated and complicated tasks by issuing it instructions. We give the computer instructions, usually in the form of programs, so it will perform the data processing. An instruction is typically a group of characters the computer understands. A single instruction might be to total 2 + 2. A program is a series, or set, of instructions that gives us a more complex result, such as producing a report listing all the company's customers living in the postal ZIP code 95123.