1920s-1950s: The EAM Era From the 1920s throughout the mid-1950s, punched-card technology 4improved with the addition of more punched-card devices and more sophisticated capabilities. The electromechanical accounting machine (EAM) family of punched-card devices includes the card punch, verifier, reproducer, summary punch, interpreter, sorter, collator, and accounting machine.Most of the devices in the 1940s machine room were "programmed" to perform a particular operation by the insertion of a prewired control panel. A machine-room operatorin a punched-card installation had the physically challenging job of moving heavy

1904-1995: Dr. John V. Atanasoff In 1939 Dr. John V.Atanasoff, a professor at Iowa State University, and graduate student Clifford E. Berry assembled a prototype of the ABC (for Atanasoff Berry Computer} to cut the time physics students spent making complicated calculations. A working model was finished in 1942. Atanasoff's decisions—to use an electronic medium with vacuum tubes, the base-2 numbering system, and memory and logic circuits—set the direction for the modern computer. Ironically, Iowa State failed to patent the device and IBM, when contacted about the ABC, airily responded, "IBM will never be interested in an electronic computing machine." A 1973 federal court ruling officially credited Atanasoff with the invention of the automatic electronic digital computer.

1942: The First Computer, The ABC During the years 1935 through 1938, Dr. Atanasoff had begun to think about a machine that could reduce the time it took for him and his physics students to make long, complicated mathematical calculations. The ABC was, in fact, born of frustration. Dr. Atanasoff later explained that one night in the winter of 1937, "nothing was happening" with respect to creating an electronic device that could help solve physics problems. His "despair grew," so he got in his car and drove for several hours across the state of Iowa and then across the Mississippi River. Finally, he stopped at an Illinois madhouse for a drink. It was in this roadhouse that Dr. Atanasoff overcame his creative block and conceived ideas that would lay the foundation for the evolution of the modern computer

1944: The Electromechanical Mark I Computer The first electromechanical computer, the MARK I, was completed by Harvard University professor Howard Aiken in 1944 under the sponsorship of IBM. A monstrous 51 feet long and 8 feet high, the MARK I was essentially a serial collection of electromechanical calculators and was in many ways similar to Babbage's analytical machine. (Aiken was unaware of Babbage's work, though.) The Mark I was a significant improvement, but IBM's management still felt electromechanical computers would never replace punched-card equipment.

1946: The Electronic ENIAC Computer Dr. John W. Mauchly (middle) collaborated with J. Presper Eckert, Jr. (foreground) at the University of Pennsylvania to develop a machine that would compute trajectory tables for the U.S. Army. (This was sorely needed; during World War II, only 20% of all bombs came within 1000 feet of their targets.) The end product, the first fully operational electronic computer, was completed in 1946 and named the ENIAC (Electronic Numerical Integrator and Computer). A thousand times faster than its electromechanical predecessors, it occupied 15,000 square feet of floor space and weighed 30 tons. The ENIAC could do 5000 additions per minute and 500 multiplications per minute. Unlike computers of today that operate in binary, it operated in decimal and required 10 vacuum tubes to represent one decimal digit. The ENIAC's use of vacuum tubes signaled a major breakthrough. (Legend has it that the ENIAC's 18,000 vacuum tubes dimmed the lights of Philadelphia whenever it was activated.) Even before the ENIAC was finished, it was used in the secret research that went into building the first atomic bomb at Los Alamos.

1951: The UNIVAC I and the First Generation of Computers The first generation of computers (1951-1959), characterized by the use of vacuum tubes, is generally thought to have begun with the introduction of the first commercially viable electronic digital computer. The Universal Automatic Computer (UNIVAC I for short), developed by Mauchly and Eckert for the Remington-Rand Corporation, was installed in the U.S. Bureau of the Census in 1951. Later that year, CBS News gave the UNIVAC I national exposure when it correctly predicted Owight Eisenhower's victory over Adlai Stevenson in the presidential election with only 5% of the votes counted. Mr. Eckert is shown here instructing news anchor Walter Cronkite in the use of the UNIVAC I. 1954: The IBM 650 Not until the success of the UNIVAC I did IBM make a commitment to develop and market computers. IBM's first entry into the commercial computer market was the IBM 701 in 1953. However, the IBM 650 (shown here), introduced in 1954, is probably the reason IBM enjoys such a healthy share of today's computer market. Unlike some of its competitors, the IBM 650 was designed as a logical upgrade to existing punched-card machines. IBM management went out on a limb and estimated sales of 50—a figure greater than the number of installed computers in the entire nation at that time. IBM actually installed 1000. The rest is history.

1907-1992: "Amazing" Grace Murray Hopper Dubbed "Amazing Grace" by her many admirers, Dr. Grace Hopper was widely respected as the driving force behind COBOL, the most popular programming language, and a champion of standardized programming languages that ore hardware-independent. In 1959 Dr. Hopper led an effort that laid the foundation for the development of COBOL. She also created a compiler that enabled COBOL to run on many types of computers. Her reason: "Why start from scratch with every program you write when a computer could be developed to do a lot of the basic work for you over and over again?To Dr. Hopper's long list of honors, awards, and accomplishments, add the fact that she found the first "bug" in a computer—a real one. She repaired the Mark II by removing a moth that was caught in Relay Number II. From that day on, every programmer has debugged software by ferreting out its bugs, or errors, in programming syntax or logic.

1959: The Honeywell 400 and the Second Generation of Computers The invention of the transistor signaled the start of the second generation of computers (1959-1964). Transistorized computers were more powerful, more reliable, less expensive, and cooler to operate than their vacuum-tubed predecessors. Honeywell (its Honey-well 400 is shown here) established itself as a major player in the second generation of computers. Burroughs, Univac, NCR, CDC, and Honeywell—IBM's biggest competitors during the 1960s and early 1970s&151;became known as the BUNCH (the first initial of each name).

1963: The PDP-8 Minicomputer During the 1950s and early 1960s, only the largest companies could afford the six- and seven-digit price tags of mainframe computers. In 1963 Digital Equipment Corporation introduced the PDP-8 (shown here). It is generally considered the first successful minicomputer (a nod, some claim, to the playful spirit behind the 1960s miniskirt). At a mere $18,000, the transistor-based PDP-8 was an instant hit. It confirmed the tremendous demand for small computers for business and scientific applications. By 1971 more than 25 firms were manufacturing minicomputers, although Digital and Data General Corporation took an early lead in their sale and manufacture.

1964: The IBM System 360 and the Third Generation of Computers The third generation was characterized by computers built around integrated circuits. Of these, some historians consider IBM's System 360 line of computers, introduced in 1964, the single most important innovation in the history of computers. System 360 was conceived as a family of computers with upward compatibility; when a company outgrew one model it could move up to the next model without worrying about converting its data. System 360 and other lines built around integrated circuits made all previous computers obsolete, but the advantages were so great that most users wrote the costs of conversion off as the price of progress.

1964: BASIC—More than a Beginner's Programming Language In the early 1960s, Dr. Thomas Kurtz and Dr. John Kemeny of Dartmouth College began developing a programming language that a beginner could learn and use quickly. Their work culminated in 1964 with BASIC. Over the years, BASIC gained widespread popularity and evolved from a teaching language into a versatile and powerful language for both business and scientific applications. From micros to mainframes, BASIC is supported on more computers than any other language.

1971: Integrated Circuits and the Fourth Generation of Computers Although most computer vendors would classify their computers as fourth generation, most people pinpoint 1971 as the generation's beginning. That was the year large-scale integration of circuitry (more circuits per unit of space) was introduced. The base technology, though, is still the integrated circuit. This is not to say that two decades have passed without significant innovations. In truth, the computer industry has experienced a mind-boggling succession of advances in the further miniaturization of circuitry, data communications, and the design of computer hardware and software.

1975: Microsoft and Bill Gates In 1968, seventh grader Bill Gates and ninth grader Paul Alien were teaching the computer to play monopoly and commanding it to play millions of games to discover gaming strategies. Seven years later, in 1975, they were to set a course which would revolutionize the computer industry. While at Harvard, Gates and Alien developed a BASIC programming language for the first commercially available microcomputer, the MITS Altair. After successful completion of the project, the two formed Microsoft Corporation, now the largest and most influential software company in the world. Microsoft was given an enormous boost when its operating system software, MS-DOS, was selected for use by the IBM PC. Gates, now the richest man in America, provides the company's vision on new product ideas and technologies.

1977: The Apple II Not until 1975 and the introduction of the Altair 8800 personal computer was computing made available to individuals and very small companies. This event has forever changed how society perceives computers. One prominent entrepreneurial venture during the early years of personal computers was the Apple II computer (shown here). Two young computer enthusiasts, Steven Jobs and Steve Wozniak (then 21 and 26 years of age, respectively), collaborated to create and build their Apple II computer on a makeshift production line in Jobs' garage. Seven years later, Apple Computer earned a spot on the Fortune 500, a list of the 500 largest corporations in the United States.

1981: The IBM PC In 1981, IBM tossed its hat into the personal computer ring with its announcement of the IBM Personal Computer, or IBM PC. By the end of 1982,835,000 had been sold. When software vendors began to orient their products to the IBM PC, many companies began offering IBM-PC compatibles or clones. Today, the IBM PC and its clones have become a powerful standard for the microcomputer industry.

1982: Mitchell Kapor Designs Lotus 1-2-3 Mitchell Kapor is one of the major forces behind the microcomputer boom in the 1980s. In 1982, Kapor founded Lotus Development Company, now one of the largest applications software companies in the world. Kapor and the company introduced an electronic spreadsheet product that gave IBM's recently introduced IBM PC (1981) credibility in the business marketplace. Sales of the IBM PC and the electronic spreadsheet, Lotus 1-2-3, soared.

1984: The Macintosh and Graphical User Interfaces In 1984 Apple Computer introduced the Macintosh desktop computer with a very friendly graphical user interface& #151: proof that computers can be easy and fun to use. Graphical user interfaces (GUIs) began to change the complexion of the software industry. They hove changed the interaction between human and computer from a short, character-oriented exchange modeled on the teletypewriter to the now familiar WIMP interface—Windows, Icons, Menus, and Pointing devices. Courtesy of Apple Computer, Inc.

1985 to present: Microsoft Windows Microsoft introduced Windows, a GUI for IBM-PC-compatible computers in 1985; however, Windows did not enjoy widespread acceptance until 1990 with the release of Windows 3.0. Windows 3.0 gave a huge boost to the software industry because larger, more complex programs could now be run on IBM-PC compatibles. Subsequent releases, including Windows 95, Windows NT, and Windows 98 make personal computers even easier to use, fueling the PC explosion of the 1990s