Foundations of information systems : BIS 1202 Lecture 2: Computer Hardware and information technology infrastructure

Learning objectives After this lecture, you will be able to: categorize the type of computer system that a business uses; recognize the different components of a computer; specify the components needed for the purchase of a personal computer; define the criteria for selection of hardware. Identify the computer systems and peripherals you would acquire or recommend for a business of your choice, and explain the reasons for your selections 2

Computer Hardware and information technology infrastructure. Computers are at the core of every modern information system A computer is a physical device that takes data as input, transforms these data according to stored instructions, and outputs the processed information. A computer system consists of; Central Processing unit-Manipulates raw data into a more useful form and controls the other parts of the computer system 3

Computer Hardware and information technology infrastructure. A computer system consists of; Primary storage-stores data and program instructions during processing Secondary storage- e.g., magnetic and optical disks, flash disks, store data and programs when they are not being used in processing. Input devices-such as key board and mouse convert data and instructions into electronic form for input into the computer 4

Computer Hardware and information technology infrastructure. A computer system consists of; Output devices- such as printers and video display terminals, convert electronic data produced by the computer system and display them in a form that people can understand Communication devices-provide connections between the computer and communications network. Buses are circuitry paths for transmitting data and signals among the parts of the computer system 5

Computer Hardware and information technology infrastructure. The computer system 6 Communications devices Secondary storage Magnetic disk Optical disk Magnetic tape Central processing unit Primary storage Input devices Keyboard Mouse Touch screen Output devices Printers Video display terminals Audio output buses

Computer systems and components are divided into; Hardware: the physical components of the computer Software: the set of instructions that direct the hardware to perform particular tasks 7 Computer Hardware and information technology infrastructure.

Hardware components Input device: Hardware used to enter data, information or instructions into a computer-based information system. Central processing unit (CPU): The processor found in a computer system that controls all of the computer’s main functions and enables users to execute programs or process data. Memory: A temporary means of storing data awaiting processing, instructions used to process data or control the computer system, and data or information that has been processed. Storage devices: A permanent means of storing data and programs until they are required. Output devices: Translate the results of processing – output – into a human readable form.

Input devices Natural keyboard: Keys are arranged so that users can locate them more quickly and easily in a way that makes prolonged use more comfortable. Graphical user interface (GUI): Allows the user to control the operation of a computer program or item of computer hardware using a pointing device, such as a mouse by selecting options from icons and menu options. Mouse: A pointing device found on most modern personal computers.

Input devices conts..  Optical character recognition (OCR): Software that attempts to recognise individual characters.  Optical mark recognition (OMR): Detection and recognition of simple marks made on a document.  Bar code: A means of displaying a unique identification number as a series of thick and thin lines.  Universal product code: A standard for defining bar codes used frequently in retailing. Bar code reader: Measures the intensity of a light beam reflected from a printed bar code to identify the digits making up a unique identification number. Touch screen: A transparent, pressure-sensitive covering that is attached to the screen of the monitor. Users make selections and control programs by pressing onto the screen.

Input devices conts.. Graphics tablet: Used in the same way as a writing pad; a stylus is used to draw images on a rigid pad located near to the computer. Video capture card: The video capture card records and stores video sequences (motion video). Sound card: A sound card allows a personal computer to play speech, music and other sounds. A sound card can also be used to capture sound, music and speech from a variety of sources. Voice recognition: The facility to control a computer program or carry out data entry through spoken commands via a microphone connected to a sound card. Digital Cameras Can take pictures and load them on to your computer

Output devices Considerations. Resolution: The ‘fineness’ of the image that can be displayed, expressed as number of pixels (picture elements) – the individual dots that make up an image on the screen. Dot pitch: A method of gauging the quality of a monitor’s display that involves measuring the distance between the pixels on the screen. The devices include; Visual display unit (VDU): A monitor connected to a computer system, traditionally used to describe character- based terminals. Video monitors use CRT (Cathode Ray Technology) similar to TVs Liquid crystal displays (LCD) are usually used for portable computers

Output devices cont... Video projector: A computer system can be connected directly to a projector so that output is directed to a projection screen. Plotter: A plotter uses a number of different coloured pens to draw lines upon the paper as it moves through the machine. MIDI (musical instrument digital interface): MIDI connections allow users to control musical instruments or synthesise any sounds or effects required in order to play the music.

Classification of Computers Contemporary computers can be categorized as mainframes, midrange computers, pc’s, work stations and super computers. Managers need to understand the capabilities of each of these types of computers, and why some types are more appropriate for certain processing work than others Supercomputers The largest, most powerful, and most expensive Used by universities, research institutions, and large corporations Mainframe Computers Less powerful and less expensive than supercomputers Used by businesses with large amounts of data that need to be stored in a central computer 14

Classification of Computers (Cont.) Midrange Computers Often used as the host computer in a network of smaller computers Manufacturers: DEC (VAX), IBM (AS/400), and Hewlett-Packard 15

Classification of Computers (Cont.) Microcomputers Networks of microcomputers are replacing mainframes Sometimes called workstations 16

Classification of Computers (Cont.) Microcomputers (cont.) The microprocessor chip Traditionally manufactured by Intel AMC and Cyrix are other manufacturers Macintosh are built around Motorola’s PowerPC chips Sun develops its own microprocessors and computers 17

Figure 3.1 Different forms of computer system

Computer Peripherals Any hardware that can improve the functionality of the computer.

Computer Power Clock rate : Measured in MHz (megahertz, or millions of pulses per second). Bus: A collection of wires through which data is transmitted from one part of a computer to anotherdatacomputer Throughput: Output relative to input; the amount passing through a system from input to output (especially of a computer program over a period of time) 20

Considerations in Purchasing Hardware What should you consider when buying hardware? Power -- speed, size of memory, storage capacity Expansion and upgrade capability Ports for external devices like printers, hard disks, communication devices Ergonomics: Keyboard, Monitor 21

Considerations in Purchasing Hardware (Cont.) What should you consider when buying hardware (cont.)? Vendor reliability, warranty policy, vendor support Compatibility Cost 22

Considerations in Purchasing Hardware (Cont.) 23 Factor What to Look For PowerGreater frequency and word size, larger ExpandabilityGreater number of board slots for additional RAM PortsGreater number of ports for printer, external hard disk, communication devices and other peripherals ErgonomicsGreater comfort and safety CompatibilityComparability with many other computers and peripheral devices, as swell as software packages SupportAvailability of telephone and on-line support for troubleshooting WarrantyLonger warranty period Cost Lower cost

Summary Computer components and their functions Computer communication Categories of computers have different strengths and weaknesses Understand commonly used hardware terminology Identify and evaluate key criteria for purchasing decisions 24