1Introduction to Information Technology

1.1 Computer Literacy

Computer literacy is the knowledge and ability to use computers and technology efficiently. Computer literacy can also refer to the comfort level for people touse computer programs and other applications that are associated with computers. Another valuable component of computer literacy is to know how computers work and operate.

1.2 Information System

An information system has five parts: people, procedures, software, hardware, and data. People: end users who use computers to make themselves more productive; Procedures: specify rules or guidelines for computer operations; Software: provides step-by-step instructions for computer hardware; Hardware: equipments that process the data to create information, including keyboard,

mouse, monitor, system unit, and other devices; Data: raw, unprocessed facts, including text, numbers, images, and sounds, etc.

信息技术基础（IT Fundamentals）双语教程

1.3 Information Technology (IT)

Information Technology (IT) is the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware. In short, IT deals with the use of electronic computers and computer-based tools to convert, store, protect, process, transmit and retrieve information, securely.

1.4 What is a Computer?

A computer is an electronic device, operating under the control of instructions stored in its own memory, which can accept data, manipulate the data according to specified rules, produce results, and store the results for future.

1.5 Components of a Computer

1.5.1 Hardware

Hardware is the electronic circuits and mechanical parts that physically make up the computer. These components include a system unit, input devices, output devices, storage devices, and communication devices. Figure I-1-1 shows some common computer hardware components.

1.5.1.1 System Unit

System unit is also known as base unit. It is the main body of a desktop computer, typically consisting of a metal or (rarely) plastic enclosure containing the chassis, CPU, memory, bus, and ports, but does not include the keyboard or monitor, or any peripheral devices.

1.5.1.2 Input Devices

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1. Introduction to Information Technology

An input device is any hardware component that allows you to enter data or instructions into a computer. Six widely used input devices are the keyboard, mouse, microphone, scanner, digital camera, and PC video camera (ref. Figure I-1-1).

1.5.1.3 Output Devices

An output device is any hardware component that conveys information to one or more people. Three commonly used output devices are printers, monitors, and speakers (ref. Figure I-1-1).

Figure I-1-1 Hardware Components of a Computer

1.5.1.4 Storage Devices

A storage device is capable of storing data. The term usually refers to mass storage devices, such as disk and tape drives.

1.5.1.5 Communication Devices

A communication device is a hardware component that enables a computer to send (transmit) and receive data, instructions, and information to and from one or more computers. A widely used communication device is Modem (ref. Figure I-1-1).

1.5.1.6 Bus (Data Path)

The above five units (system unit, input devices, output devices, storage devices, and communications devices) are interconnected through various buses. A bus is a set of wires (a physical path) through which data and instructions are transmitted from one part of a computer to another (ref. Figure I-1-2).

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信息技术基础（IT Fundamentals）双语教程

Error: Reference source not foundFigure I-1-2 Bus (Data Path)

(1) Data BusData bus transfers actual data whereas the address bus transfers information about where

the data should go.(2) Address BusAddress bus is the collection of wires connecting the CPU with main memory that is used

to identify particular locations (addresses) in main memory.(3) Control BusControl bus is the physical connections that carry control information between the CPU

and other devices within the computer. Whereas the data bus carries actual data that is being processed, the control bus carries signals that report the status of various devices. For example, one line of the bus is used to indicate whether the CPU is currently reading from or writing to main memory.

1.5.2 Software

Software, also called a program, is the set of all the instruction combinations to control the computer. There are two categories of software: system software and application software.

1.5.2.1 System Software

System software consists of the programs that manage and control the hardware so that application software can perform a task. It is an essential part of the computer system. Two types of system software are the operating system and utility programs.

(1) Operating System (OS)Operating system (OS) is the most important program that runs on a computer. Every

general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

E.g., Vista, Windows XP, Windows 2000/2003, Linux, etc.(2) Utility ProgramsUtility program (also known as service program, service routine, tool, or utility routine) is

a type of computer software. It is specifically designed to help manage and tune the computer hardware, operating system or application software, and perform a single task or a small range of tasks. Utility software has long been integrated into most major operating systems.

E.g., disk defragmenters, virus scanners, compression utilities, etc.1.5.2.2 Application Software

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1. Introduction to Information Technology

Application software (also called end-user programs) is a subclass of computer software that employs the capabilities of a computer directly and thoroughly to a task that the user wishes to perform. This should be contrasted with system software which is involved in integrating a computer's various capabilities, but typically does not directly apply them in the performance of tasks that benefit the user. In this context the term application refers to both the application software and its implementation.

Typical examples of software applications are database programs, word processors, spreadsheets, and media players, etc.

Figuratively speaking, application software sits on top of system software because it is unable to run without the operating system and system utilities.

1.6 Categories of Computers

Supercomputers Mainframe Computers Midrange Computers Minicomputers Personal Computers

1.6.1 Supercomputers

A supercomputer (ref. Figure I-1-3, Cray-2 was the world's fastest computer from 1985 to 1989) is a computer that led the world (or was close to doing so) in terms of processing capacity, particularly speed of calculation. It is the fastest, most powerful and most expensive computer.

1.6.2 Mainframe Computers

A mainframe computers (ref. Figure I-1-4, Honeywell-Bull DPS 7 mainframe, circa 1990) is a very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously.

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信息技术基础（IT Fundamentals）双语教程

Figure I-1-3 Supercomputer Figure I-1-4 Mainframe Computer

1.6.3 Midrange Computers

A midrange computer (ref. Figure I-1-5) refers to computers that are more powerful and capable than personal computers but less powerful and capable than mainframe computers. In the past, midrange computers were known as minicomputers.

1.6.4 Minicomputers

A minicomputer (ref. Figure I-1-6) is a midsized computer. In size and power, minicomputers lie between workstations and mainframes. In the past decade, the distinction between large minicomputers and small mainframes has blurred, however, just as the distinction between small minicomputers and workstations has.

1.6.5 Personal Computers

A personal computer is a small, single-user computer based on a microprocessor. It can perform all of its input, processing, output, and storage activities by itself and contains a processor, memory, one or more input and output devices, and storage devices.

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1. Introduction to Information Technology

Figure I-1-5 Midrange Computer Figure I-1-6 Minicomputer

1.6.5.1 Desktop Computers

A desktop computer (ref. Figure I-1-7) is a computer made for use on a desk in an office or at home and is distinguished from portable computers such as laptops or PDAs. Desktop computers are also known as microcomputers.

1.6.5.2 Notebook Computers

Notebook computer (also called notebook or laptop, ref. Figure I-1-8) is a small mobile computer, small enough that it can sit on your lap.

Figure I-1-7 Desktop Computer Figure I-1-8 Notebook Computer

1.6.5.3 Tablet PC

Tablet PC (ref. Figure I-1-9) is a notebook or slate-shaped mobile computer. Its touchscreen or digitizing tablet technology allows the user to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse. The computer is linked to a network using a wireless or wired link.

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信息技术基础（IT Fundamentals）双语教程

Figure I-1-9 Tablet PC

1.6.5.4 Personal Digital Assistants (PDA)

PDA is a handheld device that combines computing, telephone/fax, Internet and networking features. A typical PDA can function as a cellular phone, fax sender, Web browser and personal organizer. Figure I-1-10 shows PDA from Apple (Newton).

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