Introduction to Computer Science 1 Chapter 1: Information Communication Technology

Information Communication Technology 1.Describe the five main components of an information system 2.Describe the difference between the mainframe, minicomputer, supercomputer and the personal computers 3.Explain the features of the hardware devices used for input, processing, storage, output and communications 4.Explain the features of some common storage devices 5.Understand how computers can be connected to a network, Internet and the Web 2

Information System (IS) Information systems are systems involved in the gathering, processing, distribution and use of information such as support human activity systems. Most common view of an information system is one: Input-Process-Output. 1.1 The five parts of an information system: people, procedures, software, hardware and data 3

4 People There are many roles for people in information systems Systems Analyst Programmer Technician Engineer Network Manager MIS (Manager of Information Systems) Data entry operator

Procedures Procedures are the policies that govern the operation of a computer system, a procedure is a series of documented actions taken to achieve something, a procedure is more than a single simple task. Hardware The term hardware refers to machinery as CPU, and among the Support equipment are input And output devices, storage devices and communication devices. 1.1 The five parts of an information system: people, procedures, software, hardware and data 5

6 Software The term software refers to computer programs. Programs are generally stored on some input / output medium- often a disk or tape. Data Data are facts that are used by program to produce useful information, data are generally stored in machine-readable from on disk or tape until the computer needs them.

Components of an Information System 7

1.2 Four kinds of computers – microcomputer, minicomputer, mainframe, and supercomputer 8 The Mainframe Computer A mainframe is a high-performance computer used for large- scale computing purposes that require greater availability and security. In the early years of computing, the original mainframes were housed in room-sized metal frames

1.2 Four kinds of computers – microcomputer, minicomputer, mainframe, and supercomputer 9 The Microcomputer A microcomputer is a complete computer on a smaller scale and is generally a synonym for the more common term, personal computer or PC, a computer designed for an individual. Other than Desktop Computer the choice ranges as follows: Personal Digital Computer Tablet PC Towers Work Stations Laptops Hand Held Computer

1.2 Four kinds of computers – microcomputer, minicomputer, mainframe, and supercomputer 10 A microcomputer contains a: Microprocessor Memory - read-only memory and random access memory I/O ports and a bus or system of interconnecting wires a motherboard. Mini computers like the mainframe computers are used by business organization, it can support the simultaneous working of up to 100 users, usually maintained in business organizations for the maintenance of accounts and finances. Mini computer is a computer of a size intermediate between a microcomputer and a mainframe and it’s term no longer much used. The Mini computer

The Super Computer It is somewhat similar to mainframe computers and is used in economic forecasts and engineering designs. A supercomputer is a computer that performs at or near the currently highest operational rate for computers, A supercomputer is typically used for scientific and engineering applications that must handle very large databases 1.2 Four kinds of computers – microcomputer, minicomputer, mainframe, and supercomputer 11

Hardware devices for input, processing, storage, output and communications Input Devices An input device is any hardware component that allows you to enter data, Some popular include keyboard, mouse, trackballs, and light pens, digital camera, scanner, and microphone. Keyboard: This is the most common input device for home and commercial users, the keys on computer keyboards are often classified as follows: Alphanumeric keys -- letters and numbers Punctuation keys -- comma, period, semicolon, and so on. Special keys -- function keys, control keys, arraw keys, Caps Lock key, and so on. 12

Output Devices It refers to any machine capable of representing information from a computer. This includes display screens, printers and so on a)Display screen: Most display screens work under the same principle as a television, using a cathode ray tube (CRT). A CRT works by moving an electron beam back and forth across the back of the screen. Each time the beam makes a pass across the screen, it lights up phosphor dots on the inside of the glass tube, thereby illuminating the active portions of the screen Hardware devices for input, processing, storage, output and communications 13

b) printer: Dot-Matrix Printer – set of steel pins strike an inked ribbon onto paper producing any desired sequence of dots, Ink-Jet Printer - fires a jet of liquid ink through tiny holes and it gives high resolution for almost professional quality. Laser Printer – works like a photocopier, powdered ink is fused onto paper by heat and pressure. The sharpness of the print is considered to be of very high resolution and suitable. Hardware devices for input, processing, storage, output and communications 14

Some Common Storage Devices Hard Drive The hard drive is the primary device that a computer uses to store information. The hard drive stores programs, data files, saves files, and organizes files. The hard drive is located inside the computer case. The hard drive, magnetically stores data on stacks of rotating disks called platters. Hardware devices for input, processing, storage, output and communications 15

16 Floppy Drive The floppy drive stores and retrieves information on a floppy disk. CD -ROM Drive is a device that reads information stored on a compact disc, CD-ROM stands for Compact Disc Read Only Memory. One CD is equal to the space in over 40 floppy disc. Hardware devices for input, processing, storage, output and communications