Chapter 1 ESSENTIAL COMPUTER CONCEPTS What Is a

Chapter 1 ESSENTIAL COMPUTER CONCEPTS What Is a Computer Types of Computers Computer Hardware Data Communications Computer Software EC 4 EC 6 EC 9 EC 22 EC 26

What Is a Computer? Computers have become essential tools in almost every type of activity in virtually every type of business. A computer is defined as an electronic device that accepts input, processes data, stores data, and produces output. It is a versatile tool with the potential to perform many different tasks. A computer system includes a computer, peripheral devices, and software. The physical components of a computer are referred to as hardware. The design and construction of a particular computer is referred to as its architecture, or configuration. The technical details about each component are called specifications. For example, a computer system might be configured to include a printer; a specification for that printer might be a print speed of eight pages per minute or the capacity to print in color. The computer itself takes care of the processing function, but it needs additional components, called peripherals, to accomplish its input, output, and storage functions. . Software refers to the intangible components of a computer system, particularly the programs, or lists of instructions, that the computer needs to perform a specific task. Software is the key to a computer’s versatility. When your computer is using word processing soft ware—for example, the Microsoft Word program—you can type memos, letters, and reports. When your computer is using accounting software, you can maintain information about what your customers owe you and display a graph showing the timing of customer payments.

The computer processes the report according to your commands and the instructions contained in the software—the title becomes centered and all the text double-spaced. Processing changes the data you have input, for example, by moving text, sorting lists, or perfomiing calculations. Or, you might choose to import from another computer an illustration, text, or numeric data such as stock prices. This processing takes place on the main circuit board of the computer, also referred to as the motherboard, which contains the computer’s major electronic components. The electronic components of the main circuit board are referred to as processing hardware. Using a computer to type your report has several advantages. The first is the speed at which you can perform the task. Second, the capability of storing the answer and using it over and over again, in so many different ways, makes using a computer the most effective way to perform many personal and clerical tasks. Finally, an important advantage is sharing data and output with others. You make a note to find out whether Paik employees will need to share their data.

Types of Computers Personal computers are not the only way to compute; there are other types of computers, which are classified by their size, speed, and cost. Microcomputers, also called personal computers (PCs), are the computers typically used by a single user, usually at home or at the office. They come in many shapes and sizes, as you can see in A standard desktop microcomputer fits on a desk and runs on power from an electrical wall outlet. The display screen is usually placed on top of the horizontal desktop case.

A microcomputer with a tower case contains the same basic components as a standard desktop microcomputer, but the vertically oriented case is large and allows more room for expansion. The tower unit can be placed on the floor to save desk space. A notebook computer is small and light, giving it the advantage of portability that standard desktop computers do not have. A notebook computer can run on power from an electrical outlet or batteries.

A personal digital assistant (PDA), or palm-top computer achieves even more portability than a notebook computer by shrinking or eliminating some standard components, such as the key board. On a keyboardless PDA, a touch-sensitive screen accepts characters drawn with your finger. PDAs easily connect to desktop computers to exchange and update information.

A TYPICAL MINICOMPUTER HANDLES PROCESSING TASKS FOR MULTIPLE USERS The minicomputer stores data for all the users in one centralized location. Terminals act as each user’s main input and output device. The terminal has a keyboard for input and a display screen for output, but it does not process the user’s data. Instead, processing requests must be transmitted from the terminal to the minicomputer.

Mainframe computers, are larger and more powerftil than minicomputers. As with a minicomputer, one mainframe computer performs process ing tasks for multiple users on terminals. However, the mainframe can handle many more users than a minicomputer. Mainframes are typically used to provide centralized storage, processing, and management for large amounts of data. The price of a typical mainframe computer can be several hundred thousand dollars.

The largest and fastest computers, called supercomputers, were first developed for high-volume computing tasks such as weather prediction. Supercomputers like the one shown in Figure 6 are also being used by large corporations when the tremendous volume of data ould seriously delay processing on a mainframe computer. Although its cost can be several million dollars, a supercomputer’s processing speed is so much faster than that of microcomputers, minicomputers, and mainframes that the investment can be worthwhile.

Computer Hardware You input data and commands by using an input device such as a keyboard or a mouse. The computer can also receive input from a storage device. This section takes a closer look at the input devices you might use. Output and storage devices are covered in later sections. The most frequently used input device is a keyboard. The top keyboard in Figure 7 is a standard 101 -key keyboard. Newer keyboards such as the bottom keyboard in Figure 7, are ergonomic, which means that they have been designed to fit the natural placement of your hands and should reduce your risk of repetitive-motion injuries. All keyboards consist of three major parts: the main keyboard, the keypads, and the function keys. input Devices

TRADITIONAL 101 -KEY KEYBOARD

All microcomputers also should be equipped with a pointing device. The pointing device controls a pointer on the display screen. Using a pointing device an important skiil because most microcomputers depend on such devices to select com mands and manipulate text or graphics on the screen. Computers that input from terminals do not normally use pointing devices. Computers used for presentations often feature remote input devices, such as the remote control used for a TVIVCR. The remote input device allows you to control the pointer from the back of the auditorium. Now that you have read about input devices, refer back to the computer advertisement shown in Figure 1 at the beginning of the chapter. Can you list the input devices included with the adver tised system? A mouse and a keyboard are considered essential peripheral devices, so advertise ments do not always list them. Unless the ad specifies some other input device, such as a track ball, you can safely assume the computer comes equipped with a traditional keyboard and mouse.

A track point is a small eraser- like device embedded among typing keys. To control the on- screen pointer, you push the track point up, left, right, or down. Buttons for clicking and double-clicking are located in front of the spacebar. A track ball is like an upside- down mouse. By rolling the ball with your fingers, you control the onscreen pointer. Buttons for clicking are often located above or to the side of the track ball. A touch pad is a touch-sensitive device. By dragging your finger over the surface, you control the on-screen pointer. Two buttons equivalent to mouse buttons are located in front of the touch pad.