1200S—Manual Calculating Devices

Manual calculating devices required the use of hands to move components on the device.

The first calculation device, the abacus, was used in China. It involved manually moving beads to do calculations. Below is a picture of an abacus.

Figure 1 Abacus

1600S—Mechanical Calculators

Mechanical calculators used wheels, gears, and counters.

1642: Blaise Pascal invented the Pascaline, which is a mechanical calculator. The machine used some principles of the abacus, but used wheels to move counters.

1800S—Punched Cards

Punched cards use holes following a specific pattern to represent the instructions given to the machine or stored data. The idea of storing data and program instructions on punched cards came from the Jacquard loom. It used pasteboard cards with patterns of punched holes to produce mass quantity of fabrics weaved in a variety of patterns. Each punched card represents a pattern and the punched card can be fed through the Jacquard loom to produce weaved fabrics of the pattern repeatedly. Similarly, different program instructions can be stored on separate punched cards, which can be fed through the computing machine repeatedly. Using punched cards, program instructions and data can be stored.

1834: Charles Babbage designed a new general-purpose calculating device, the Analytical Engine, which is the ancestor of modern computers. It included the essential components of present-day computers, which are input, process, storage, and output of data.

Babbage's assistant, Augusta Ada King, Countess of Lovelace and daughter of English poet Lord Byron, would create the instruction routines stored on punched cards to tell the machine what to do. Instruction routines used by the computer are known as "computer programs." She is thus the first female computer programmer, and in her honor, the U.S. Defense Department named the programming language ADA.

Below is an image of an analytical engine.

Figure 2 Analytical engine

1890: Herman Hollerith designed an electronic punched card tabulating device that enabled the U.S. Census Bureau to tabulate the 1890 census in six months, which would have otherwise taken more than 7 years. Hollerith’s machine used punched cards to store data instead of instruction routines.

1896: Hollerith thought the business world could benefit from the electronic punched card tabulating device, and founded Tabulating Machine Company, which later became International Business Machines (IBM) in 1924.

1940S—Vacuum Tubes

Vacuum tubes are used to control the flow of electrons. Since vacuum tubes responded faster than mechanical components, faster computations were possible. But, the tubes consumed a lot of power and burned out quickly.

Below is a picture of vacuum tubes.

Figure 3 Vacuum tubes

1945: The first computer prototype using vacuum tubes, ENIAC (Electronic Numerical Integrator and Computer) was designed to calculate trajectory tables for the U.S. Army during World War II, but it was not completed until three months after the war.

The machine was 100 feet long and 10 feet high and weighed 30 tons. It had over 18,000 vacuum tubes. But, in the first year, a total of 19,000 tubes burned out and were replaced. The ENIAC could perform 5,000 additions per second, but its operation has to be programmed manually by connecting cables and setting 6,000 switches.

The first commercially successful computer, UNIVAC was developed by Eckert-Mauchly Computer Corporation (later acquired by Remington Rand). The machine was 14.5 feet long, 7.5 feet high, and 9 feet wide. It could read 7,200 characters per second. It was priced at $930,000. Another important development was the invention of the compiler by Admiral Grace Hopper who was working at Eckert-Mauchly Computer Corporation at the time. A compiler enables program instructions to be written in English and then translated into a language that the machine can understand. This invention made the task of programming easier and faster.