The concept of inventing hardware to assist in commercial productivity is not new. For example, thousands of years ago the Chinese sought greater efficiency in calculating numbers, leading to the invention of the abacus, a hand-held mechanical device. Another hardware milestone was reached when Charles Babbage, in 1822, proposed a machine that would calculate mathematical tables; much of his design was used in later computers (Long and Long, 1999). Herman Hollerith designed a method to store numbers onto punched cards in order to calculate the 1890 census, and the company he founded eventually became IBM Corporation (Long and Long, 1999).

THE COMPUTER ERA BEGINS

The first electronic computer, the ENIAC, was developed at the University of Pennsylvania in 1946. It used vacuum tubes and weighed thirty tons. Remington Rand Corporation produced the first commercial computer, the Univac, in 1951, which also used transistors (Long and Long, 1999). Transistors replaced vacuum tubes, were far smaller, and used less power than tubes. Transistors were shortly thereafter replaced by integrated circuits, which further minimized size and lessened power requirements. The availability of integrated circuits made the first personal computer possible in 1977 when Stephen Jobs and Steve Wozniak introduced the "Apple II" (Long and Long, 1999). IBM offered their first microcomputer in 1981, and Apple's Macintosh was introduced in 1984. The Macintosh was the first popular computer with a graphical user interface (GUI), and it also had a laser printer that could combine text and pictures (Long and Long, 1999). A GUI operating system receives input from both the keyboard and a pointing device (mouse). This type of system was a boon to computer users who were not proficient or comfortable with keyboarding, and today most personal computers require the use of a mouse.

CLASSIFICATIONS AND DEFINITIONS OF COMPUTERS

There are three main classifications of computers: mainframe, minicomputer, and microcomputer. The major categories can only be used as general guidelines because of the huge variety in product lines. Computer "servers" have also been included in this discussion because of their important role in networking and Internet applications.

A mainframe computer is any large computer system, such as that used by the Internal Revenue Service. Another typical use of a mainframe computer would be for an airline ticketing system, which can have thousands of users connected to one computer. The next smaller-sized computer is termed a minicomputer. It is of medium scale and can serve up to several hundred users. The microcomputer is the smallest in size

and power, and the term is "generally synonymous with personal computer, such as a Windows PC or Macintosh, but it can refer to any kind of small computer" (CMP Net Online Encylopedia). Microcomputers can also be portable, and some have Pentium processors, fourteen-inch color screens, and multi-gigabyte hard drives. Very small computers include hand-held units and pen computers that store information the user enters with a stylus rather than a key board (Hutchinson and Sawyer, 1998).

A "server" computer is one that is used to connect a cluster of personal computers through using a local area network (LAN). World Wide Web pages are also stored on a "Webserver," which is typically a dedicated personal computer.

COMPUTER COMPONENTS

Central Processing Unit (CPU) The CPU is at the heart of all computers. All data passes through it. According to the CMP Net Online Encyclopedia:

[The CPU is] the computing part of the computer. Also called the processor, it is made up of the control unit and ALU. Today, the CPUs of almost all computers are contained on a single chip. The CPU, clock and main memory make up a computer. A complete computer system requires the addition of control units, input, output and storage devices and an operating system.

Micro, or personal, computers use microprocessors that run at approximately 500 megahertz per second. Mainframe computers measure their speed in millions of instructions per second.

Random Access Memory Random access memory (RAM) consists of microchips that allow for the temporary storage of data. RAM functions as the workspace for the CPU. The "workspace" temporarily holds the program and the active calculation before deriving an outcome. One example would be using a word processor's spelling check tool on a document. The words being checked and the program would be temporarily stored in RAM.

Input Devices Computers receive information from a variety of sources. The most common input device is a keyboard, but the pointing device (mouse or trackball) is equally important with today's GUI interface. Other input devices include video cameras, scanners, microphones, digital cameras, CD-ROMs, and voice commands that operate the computer.

Output Devices The computer monitor is an output device that is changing rapidly. For several decades computer screens only displayed letters or numbers onto a green or amber screen. As computers began using GUIs, the display device took on greater significance. The success of Apple's Macintosh computer with the graphical user interface caused Microsoft to come out with their GUI, called the Windows Operating System. Thus, all current operating systems use GUI and color for both print and images.

The standard monitor for many years has been a cathode-ray tube (CRT). CRT monitors are still very common, and they are capable of high-quality pictures. However, they are inherently bulky and relatively heavy. Portable computers became possible only when smaller and lighter-weight and display units became available. Current portable or laptop computers use LCD (liquid crystal display) panels, which are flat. LCD panels are now also being used for desktop monitors. LCD units cost about three times what comparable CRT units do, but they occupy far less space and have a very bright picture.

Computer projectors are commonly used to display data or information onto a large screen. This setup can be used to demonstrate programs, provide visuals for training, or show Web sites to large groups of people. Many businesspeople travel with both a portable computer and a computer projector to visually display information for training or to aid in sales.

The GUI and the general popularity of computers have caused significant changes in the hardware available for printing. The earliest printers were essentially automatic typewriters and had little flexibility. Today, there are a wide variety of printers currently available that are capable of nearly professional-quality output.

Laser printers, which first became available in the early 1980s, had an inherent advantage over earlier computer printers; that is, the laser beam could place tiny ink dots anywhere on the page. In practice, this means that laser printers can print fonts of any size or typeface. Further, they can print text in any direction and also print pictures. Current laser printers print at a very crisp 1200 dots per square inch and are considered to be very reliable. Color laser printers are also available, though they are much slower and also more expensive than black-and-white printers.

Ink-jet printers essentially spray ink onto the paper. They are normally very quiet, are relatively inexpensive, and have high-quality output. Further, all the newest ink-jet printers offer reasonably high-quality color printing. Both the in creased use of the Internet to download color pictures and the prevalence of digital cameras have significantly increased the popularity of color ink-jet printers.

Connection Devices Partially because of the popularity of the Internet, more and more computers of all kinds have some means of connecting to other computers. For desktop computers in schools and businesses, a network interface card (NIC) is frequently used. Portable computers and home desktop units typically use a modem as a connection device. Modems connect a personal or portable computer to dial-up networks through a regular telephone line. This connectivity has served as a boon to telecommuting and changed the way work is performed in organizations. Modems and NICs can serve as both input and output devices, depending on whether the computer is receiving or sending information.

Sound Cards and Speakers Today, any multi-media computer contains a device to reproduce sound. Typically this means that computers have a sound card that contains a mini-amplifier and connects to speakers. Sounds can also come from programs, from the Internet, and from participants in desktop teleconferences. A sound card can also function as an input device when it utilizes a microphone.

Storage Devices The number and size of storage devices are increasing. Floppy disks are portable, but they can store only a relatively small amount of information compared to the newest storage units, Zip disks, which are also portable and small. A Zip disk has about a hundred times the storage capacity of a floppy disk. Hard drives are internal storage devices that hold the computer's operating system, the application software, and other files.

A LOOK TO THE FUTURE

Computers have become a critical component of the workplace, home, and school. As we look toward the future, some trends are emerging based on the past few decades of hardware development. It is highly probable that computer hardware will become even smaller, lighter in weight, more portable, and less expensive. Keyboards may even become obsolete as voice-activation equipment becomes more sophisticated. It is also likely that there will be a greater degree of connectivity within and between systems on a global basis, as well as between home to work.

There is an increasing emphasis in elementary and secondary schools on the use of technology to access information and change the way students learn. We will see new generations of students entering the work force with surprisingly sophisticated computer skills and, perhaps, less fear of new hardware and change in general. The foreseeable future holds the promise of more and more integration of work and home by means of computers.