INFORMATION TECHNOLOGY REV 00 INFORMATION TECHNOLOGY (MIS 3301)

INFORMATION TECHNOLOGY 1.0 Computers: Tools form Information Age

The nature of Computers There fundamental characteristics: Speed Reliability Storage Capability Followed by products: Productivity Decision making Cost reduction

Computer uses Education Graphics Retailing Energy Law enforcement Transportation Money Agriculture Paperwork Government Home Health and Medicine Robotics The human connection The science Connectivity Training

Basic Components of Computer Secondary storage Secondary storage device stores data and programs Input device sends data to the central processing unit Central processing unit (CPU) executes computers instructions Memory holds data and programs currently in use Output device makes processed data (information) available Input Output Processing

Personal Computer Hardware

Input: What Goes In Input is the data that you put into the computer system for processing. Typing on a keyboard. The keys on a computer keyboard are arranged in much the same way as those on a typewriter. The computer responds to what you enter; that is, it "echoes" what you type by displaying it on the screen in front of you. Pointing with a mouse. A mouse is a device that is moved by hand over a flat surface. As the ball on its underside rotates, the mouse movement causes corresponding movement of a pointer on the computer screen. Pressing buttons on the mouse lets you select commands. Scanning with a wand reader or bar-code reader. These devices, which you have seen used by clerks in retail stores, use laser beams to read special letters, numbers, or symbols such as the zebra-striped bar codes found on many products.

Output: What Comes Out The result produced by the central processing unit. Output is usable information--that is, raw input data that has been processed by the computer into information. Common forms of output are text, numbers, graphics, and even sounds.  The most common output devices are computer screens and printers. A screen, the visible part of the monitor, can vary in its form of display, producing text, numbers, symbols, art, photographs, and even video, in full color. Printers produce printed reports as instructed by a computer program. Many printers, particularly those associated with personal computers, can print in color.

Secondary Storage Secondary storage provides additional storage separate from memory. Recall that memory holds data and programs only temporarily; thus there is a need for secondary storage. Two most common secondary storage media are: A magnetic disk can be a diskette or a hard disk.   Magnetic tape is used primarily with large computer systems. This tape usually comes on a cartridge and is similar to tape that is played on a tape recorder.

The Complete Hardware System The hardware devices attached to the computer are called peripheral equipment. Peripheral equipment includes all input, output, and secondary storage devices. In most personal computers, the CPU and disk drives are all contained in the same housing, a metal case; the keyboard, mouse, and screen are separate. In larger computer systems, however, the input, processing, output, and storage functions may be in separate rooms, separate buildings, or even separate countries. The information produced by the central processing unit may then be transmitted to the international offices, where it is printed out. Mean-while, disks with stored data may be kept at the bank headquarters, and duplicate data may be kept on disk or tape in a warehouse across town for safekeeping

Networking Many organizations find that their needs are best served by a network, a computer system that uses communications equipment to connect computers and their resources. Resources include printers and hard disks and even software and data. In one type of network, a local area network (LAN), personal computers in an office are connected together so that users can communicate with one another. Users can operate their personal computers independently or in cooperation with other computers to exchange data and share resources. The networking process can be much more complex; we will describe how large computers can be involved in networks in the chapter on networking.

The Internet The Internet, sometimes called simply "the Net," is the largest and most far-flung network system of them all, connecting users worldwide. The Internet is not really a single network but a loosely organized collection of thousands of networks.

The Internet The Internet. At his or her own computer, a user accesses the server computer Probably over the phone line. The server computer communicates with the Internet, perhaps passing on e-mail messages or requests for certain web sites, and picking up responses. Incoming messages, e-mail, or requested Internet information are returned to the original requesting computer. This back-and-forth communication goes on as long as the user wishes to remain connected to the Internet.

The Internet: Getting Connected To access the Internet, a user's computer must connect to a type of computer called a server. Each server uses the same special software called TCP/IP (for Transmission Control Protocol/Internet Protocol); it is this standard that allows different types of computers to communicate with each other. The supplier of the server computer, often called an Internet service provider (ISP), charges a fee, usually monthly, based on the amount of service provided. Once a user has chosen a service provider, he or she will be furnished with the information needed to connect to the server and, from there, to the Internet.

The Internet: Getting Around The most attractive method used to move around the Internet is called browsing. Using a program called a browser, you can use a mouse to point and click on screen text or pictures to explore the Internet, particularly the World Wide Web (WWW or the Web), an Internet subset of text, images, and sounds linked together to allow users to peruse related topics. Each different location on the Web is called a web site or, more commonly, just a site. You may have heard the term home page; this is just the first page of a web site.

Classification of Computers Computers come in sizes from tiny to monstrous, in both appearance and power. The size of a computer that a person or an organization needs depends on the computing requirements. Supercomputers Mainframes Personal Computers Notebook Computers Handheld Computers (PDA and Pocket PC) Midrange Computers (minicomputers)