In 1976, the Cray-1 supercomputer was installed at Los Alamos National Laboratory in New Mexico. It was then the fastest computer in the world,  performing 160 million  floating-point operations per second. The computer cost 8.8 million dollars and generated so much heat that it required its own refrigeration system.

By 2001, anyone could buy a computer that will fit on a desk, is 34 times as fast as the Cray-1, and has 32 times the memory. Moreover, it can compute, connect to other computers, play music CDs, and show DVD movies.

This newer computer can also burn CDs and DVDs. All of this computing power could be purchased for less than $5,000. There has certainly been a revolution.

What began as a box of parts to be assembled and tediously programmed by electronics enthusiasts has become a tool easily used by office workers and schoolchildren. The rapid growth of computer software has enabled personal computers to play games and music, to be used as intelligent typewriters, to perform mathematical calculations, and, through online capabilities, to be used for email and to connect to the vast treasures of the Internet.

Computers have become smaller, more powerful, faster, more user-friendly, and versatile enough to meet almost any need.

The Earliest Personal Computers

The January 1975 cover of Popular Electronics magazine showed a picture of the Altair 8800. This small computer was actually a kit that had to be assembled and programmed. It had no monitor (screen) and no keyboard, and it performed few functions. The kit was sold to computer hobbyists—that is, people who enjoyed building and programming the computers.

The Altair 8800 had 256 bytes of main memory, also called RAM (Random Access Memory). A major disadvantage of the Altair 8800 was that it had to be programmed in machine code, which is sequences of 0s and 1s that the computer understands. This machine code was entered using switches on the front panel of the Altair.

Beginner’s All-Purpose Symbolic Instruction Code (BASIC) is a computer language that is easy to learn and was originally developed for use on large computers. BASIC converts English-like statements into machine code.

After seeing the 1975 Popular Electronics cover, a 19-year-old college student named Bill Gates and his programmer friend, Paul Allen, decided to write a form of BASIC that would run on a computer as small as the Altair.

Gates and Allen believed there would be a demand for small computers and that these machines would need pre-written programs to run on them, called software. The two founded a company, called Microsoft, dedicated to developing software for small computers. By 1989 Microsoft’s sales reached one billion dollars, and Bill Gates would eventually be considered the richest man in the world.

Another company dedicated to the small computer, Apple Computer, was founded on April 1, 1976, by Steve Jobs, Steve Wozniak, and Ron Wayne. The first Apple computer was only a bare circuit board (a thin plate on which electronic components are placed), and sold for $666.66 to hobbyists who would need to add a power supply, a monitor, and a keyboard.

This machine, called the Apple I, sold about 200 units. Its 4,000 bytes of RAM (also called 4 kilobytes or 4K) greatly exceeded the Altair’s 256 bytes.

More Advanced Personal Computers

The Apple II was introduced in 1977 and sold for between $1,300 and $3,000, depending on the options the buyer chose. A variety of software was available for this machine. Because it did not need to be programmed, people with little knowledge of computers or electronics could use it. The Apple II was a great commercial success. Over the next 16 years, there would be many models of the Apple II, with a total of over five million units shipped.

The first Apple II had 16K bytes of memory. The last Apple II, the Apple IIgs, had 256K bytes of RAM. It contained space for inserting additional memory so the amount of RAM could be expanded to 8 MB (8 megabytes, or 8 million bytes). Since the introduction of the Apple I, memory capacity had increased by a factor of 4,000. The Apple IIgs also had a color monitor, sound, a keyboard, and a mouse.

The market for personal computers greatly expanded in 1979 with the introduction of VisiCalc, a computerized spreadsheet. A spreadsheet is a program that allows a user to enter data into a table. The user can then solve complicated “what if” problems by manipulating the data. For example, a person could change one number in a budget and see the effect it has on the entire budget. This easy and fast capability for financial analysis made

personal computers an important business tool.

By the early 1980s, over one hundred companies, such as Texas Instruments, Commodore, Tandy, and Digital Equipment Corporation, were making personal computers. Personal computers varied widely in their memory, speed, and the function capability. Their prices also varied, starting at about one hundred dollars up to thousands of dollars. There was a personal computer for every need and price range.

In 1981, IBM, which had been a leader in developing large computers, developed the first IBM personal computer (PC). It was a complete personal computer system with a great variety of software. The first IBM PC had 16K bytes of memory, expandable to 256K bytes. Its starting price was $1,565 but could cost much more depending on options. In the next eighteen months, 136,000 PCs would be sold. In 1982, other companies began producing personal computers that looked like the IBM PC. These machines would be called “clones.”

The same year, modems (standing for MOdulator/DEModulator) were introduced for personal computers. With a modem, a personal computer could transmit data to other computers, receive data, and access online databases over telephone lines. Modems allowed users of personal computers to communicate with each other through email and to connect to the Internet.

In 1983, Apple introduced a new computer called Lisa. Lisa was expensive and slow and did not sell well. However, Lisa incorporated a very important feature, the use of icons, that would influence later computers.

Before Lisa, computer users could only use commands or function keys to communicate with their computers. The introduction of pictures, called icons,  which could be moved around on the computer screen as if they were objects on a desktop, allowed users to move a pointer on a screen using a mouse or trackball and click on a picture representing a command, file, or function.

This use of icons is called GUI (for graphical user interface and pronounced goo-ee). Using GUI, a person can control the computer without having to learn commands or use special keys. GUI was first developed at the Xerox Palo Alto Research Center in the 1970s but was popularized by Lisa’s successor, the Apple Macintosh. The simplicity of using the “Mac” with its icons made it an enormous success.

Current Trends

The trend toward smaller and lighter personal computers began in 1981 with a suitcase-sized computer named the Osborne I. It was portable, although it weighed over 20 pounds, and had 64K bytes of RAM. The Osborne I cost $1,795 and was commercially successful. The Osborne  Computer Company went bankrupt within 2 years, but portable computers became popular with the advent of laptops, notebooks, and handheld computers. Today, it is not technology but the size of the keys—which have to match adult fingers—that determines how small computers can become.

An important milestone in the history of personal computers is the development of flexible software. Such software makes it possible for nonprogrammers to use programs other people have written, such as spreadsheets, word processors, and games. The great assortment of software available has made the personal computer more and more useful to individuals and has therefore increased the demand for computers. And as more people own and use personal computers, the market for a wider variety of software products also becomes greater.

Today, personal computers are almost as much a part of American life as the telephone and the automobile. They are expanding their influence in education and are an integral part of many classrooms. Businesses rely heavily on them. Personal computers have become as much a communication device as a computational one. Communication by e-mail is common and the World Wide Web houses billions of pages of information.

Computers have also become more prolific than ever before. Cities all over the world have Internet cafes, where people can buy time on personal computers. Many hotels provide access to personal computers or have facilities for connecting their guests’ laptop computers. As computers become smaller, they are also becoming wireless, using radio frequencies for communication. For less than $5,000 you can hold 8 million bytes of storage in your hand.

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Reference

Cringley, Robert X. Accidental Empires. Reading, MA: Addison-Wesley Publishing Company, Inc., 1992.

Linzmayer, Owen W. Apple Confidential. San Francisco, CA: No Starch Press, 1999.

Norton, Peter. Inside the IBM PC and PS/2, 4th ed. New York: Brady Publishing, 1991.

Osborne, Adam, and David Bunnell.  An Introduction to Microcomputers, The  Beginner’s Book, 3rd ed. Berkeley, CA: Osborne/McGraw-Hill, 1982.

Shurkin, Joel. Engines of the Mind. New York: W. W. Norton & Company, 1996.

Apple Computer.<http://www.apple.com/powermac/>.

Cray Computer. <http://www.cray.com/company/history.html>.