Lesson 1: The Development of the Computer

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In this lesson, we take a brief look at the development of the computer. By understanding its origins, you'll gain an appreciation for both the complexity and simplicity of today's computers.

After this lesson, you will be able to:

• Describe the major milestones in the development of the modern computer.

Estimated lesson time: 15 minutes

Many of us think only in terms of electronic computers, powered by electricity. (If you can't plug it in, is it a computer?) But as the definition in Funk & Wagnalls Standard College Dictionary makes clear, to "compute" is to "ascertain (an amount or number) by calculation or reckoning." In fact, the first computers were invented by the Chinese about 2500 years ago. They are called abacuses and are still used throughout Asia today.

The Abacus

The abacus, shown in Figure 1.1, is a calculator; its first recorded use was circa 500 B.C. The Chinese used it to add, subtract, multiply, and divide. But the abacus was not unique to the continent of Asia; archeological excavations have revealed an Aztec abacus in use around 900 or 1000 A.D.

Figure 1.1 The first computer

The Analytical Engine (A Pre-Electronic Computer)

The first mechanical computer was the analytical engine, conceived and partially constructed by Charles Babbage in London, England, between 1822 and 1871. It was designed to receive instructions from punched cards, make calculations with the aid of a memory bank, and print out solutions to math problems. Although Babbage lavished the equivalent of $6,000 of his own money—and $17,000 of the British government's money—on this extraordinarily advanced machine, the precise work needed to engineer its thousands of moving parts was beyond the ability of the technology of the day to carry out. It is doubtful whether Babbage's brilliant concept could have been realized using the available resources of his own century. But if it had been, it seems likely that the analytical engine could have performed the same functions as many early electronic computers.

The First Electrically Driven Computer

The first computer designed expressly for data processing was patented on January 8, 1889, by Dr. Herman Hollerith of New York. The prototype model of this electrically operated tabulator was built for the U. S. Census Bureau and computed results in the 1890 census.

Using punched cards containing information submitted by respondents to the census questionnaire, the Hollerith machine made instant tabulations from electrical impulses actuated by each hole. It then printed out the processed data on tape. Dr. Hollerith left the Census Bureau in 1896 to establish the Tabulating Machine Company to manufacture and sell his equipment. The company eventually became IBM, and the 80-column punched card used by the company, shown in Figure 1.2, is still known as the Hollerith card.

Figure 1.2 Typical 80-character punched card

The Digital Electronic Computer

The first modern digital computer, the ABC (Atanasoff-Berry Computer), was built in a basement on the Iowa State University campus in Ames, Iowa, between 1939 and 1942. The development team was led by John Atanasoff, professor of physics and mathematics, and Clifford Berry, a graduate student. This machine included many features still in use today: binary arithmetic, parallel processing, regenerative memory, separate memory, and computer functions. When completed, it weighed 750 pounds and could store 3000 bits (0.4 KB) of data.

The technology developed for the ABC machine was passed from Atanasoff to John W. Mauchly, who, together with engineer John Presper Eckert, developed the first large-scale digital computer, the Electronic Numerical Integrator and Computer (ENIAC). It was built at the University of Pennsylvania's Moore School of Electrical Engineering. Begun as a classified military project, ENIAC was destined to prepare firing and bombing tables for the U.S. Army and Navy. When finally assembled in 1945, ENIAC consisted of 30 separate units, plus power supply and forced-air cooling. It weighed 30 tons, used 19,000 vacuum tubes, 1500 relays, and hundreds of thousands of resistors, capacitors, and inductors. It required 200 kilowatts of electrical power to operate.

Although programming ENIAC was a mammoth task requiring manual switches and cable connections, it became the workhorse for the solution of scientific problems from 1949 to 1952. ENIAC is considered the prototype for most of today's computers.

Another device important to computer history is the Colossus I, an early digital computer built at a secret government research establishment at Bletchley Park, Buckinghamshire, England, under the direction of Professor Max Newman. Colossus I was designed for a single purpose: cryptanalysis—breaking codes. Using punched paper tape input, it scanned and analyzed 5000 characters per second. Colossus became operational in December 1943 and proved to be one of the most important technological aids to victory in World War II. It enabled the British to break the otherwise impenetrable German "Enigma" codes.

The 1960s and 1970s marked the era of the mainframe computer. Using the technology of ABC, ENIAC, and Colossus, large computers and emerging companies came to dominate the industry.

As these highlights show, the concept of the computer has indeed been with us for quite a while. The following table provides an overview of the evolution of modern computers—it is a timeline of important events.

NOTE

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Don't worry if you are not familiar with some terms in this timeline; they are explained in the chapters that follow, as well as in the glossary.

Year	Events
1971	The 4004—the first 4-bit microprocessor—is introduced by Intel. It boasts 2000 transistors with a clock speed of up to 1 MHz (megahertz).
1972	The first 8-bit microprocessor—the 8008—is released.
1974	The 8080 microprocessor is developed. This improved version of the 8008 becomes the standard from which future processors will be designed.
1975	Digital Research introduces CP/M—an operating system for the 8080. The combination of software and hardware becomes the basis for the standard computer.
1976	Zilog introduces the Z80—a low-cost microprocessor (equivalent to the 8080). The Apple I comes into existence, although it is not yet in wide use.
1977	The Apple II and the Commodore PET computers, both of which use a 6502 processor, are introduced. These two products become the basis for the home computer. Apple s popularity begins to grow.
1978	Intel introduces a 16-bit processor, the 8086, and a companion math coprocessor, the 8087. Intel also introduces the 8088. It is similar to the 8086, but it transmits 8 bits at a time.
1980	Motorola introduces the 68000—a 16-bit processor important to the development of Apple and Atari computers. Motorola s 68000 becomes the processor of choice for Apple.
1981	The IBM personal computer (PC) is born; it contains a 4.7-MHz 8088 processor, 64 KB (kilobytes) of RAM (random access memory) and is equipped with a version of MS-DOS 1.0 (three files and some utilities). Available mass-storage devices include a 5.25-inch floppy drive and a cassette tape drive.
1982	Intel completes development of the 80286—a 16-bit processor with 150,000 transistors. MS-DOS 1.1 now supports double-sided floppy disks that hold 360 KB of data.
1983	IBM introduces the XT computer with a 10-MB hard-disk drive. MS-DOS 2.0 arrives—it features a tree-like structure and native support for hard-disk drive operations.
1984	The first computer with an 80286 chip—the IBM AT—enters the market. It is a 6-MHz machine with a 20-MB hard-disk drive and a high-density, 1.2-MB 5.25-inch floppy-disk drive.
1985	MS-DOS 3.2, which supports networks, is released.
1986	The first Intel 80386-based computer is introduced by Compaq; it features a 32-bit processor with expanded multitasking capability (even though no PC operating system yet fully supports the feature).
1987	MS-DOS 3.3 arrives, allowing use of 1.44-MB 3.5-inch floppy-disk drives and hard-disk drives larger than 32 MB.
1988	IBM introduces the PS/2 computer series. A complete departure from previous machines, its proprietary design does not support the hardware and software available on IBM PCs or clones. Microsoft (with the help of IBM) develops OS/2 (Operating System 2), which allows 32-bit operations, genuine multitasking, and full MS-DOS compatibility. Microsoft releases MS-DOS 4.0.
1989	Intel introduces the 80486 processor; it contains an on-board math coprocessor and an internal cache controller (offering 2.5 times the performance of a 386 processor with a supporting coprocessor).
1991	MS-DOS 5.0 offers a significantly improved DOS shell.
1992	The Intel i586 processor, the first Pentium, is introduced, offering 2.5 times the performance of a 486. IBM expands OS/2, and Microsoft Windows is introduced.
1993	MS-DOS 6.0 arrives. The term multimedia (the inclusion of CD-ROM drives, sound cards, speakers, and so forth, as standard equipment on new personal computers) comes into use.
1994	Intel delivers the first 100-MHz processor. COMPAQ Computer Corporation becomes the largest producer of computers.
1995	Windows 95, code-named Chicago, is introduced by Microsoft. It features 32-bit architecture. IBM has now shipped over one million OS/2 Warp software packages. The Internet, having expanded far beyond its beginnings as a network serving government and university institutions, is now in everyday use by the rapidly growing population with access to a modem. Computer prices drop as performance increases. IBM purchases Lotus (maker of the popular Lotus1-2-3 spreadsheet).
1995 1996	Software manufacturers scramble to make their products compatible with Windows 95.
1997	Microprocessor speeds exceed the 200-MHz mark. Hard-disk drive and memory prices fall while basic system configuration sizes continue to increase. CD-ROM drives and Internet connections have become standard equipment for computers.
1998	Personal computer performance continues to soar, and PC prices continue to fall. CPU speeds exceed 450 MHz, and motherboard bus speeds reach 100 MHz. Multimedia and Internet connections have become the de facto standard for new PCs. Entry-level machines are priced near the $500 mark. Universal Serial Bus (USB) is introduced. Windows 98 becomes the standard operating system for most new personal computers.
1999	Processors exceed 600 MHz. Microsoft readies Windows 2000 for release in February 2000, as Internet shopping doubles over the holiday season.

Lesson Summary

The following points summarize the main elements of this lesson:

• The concepts that form the basis of computer technology have a long history that stretches back 2500 years.
• Rudimentary, electrically powered computers were first developed in the 1950s and 1960s.
• The "standard" personal computer has undergone several stages of evolution, characterized by improvements to the processor, internal architecture, and types of storage devices.