Presentation on theme: "Chapter 3 Uma Gupta Introduction to Information Systems 2000 by Prentice Hall. 3-1 Computer Hardware."— Presentation transcript:
Chapter 3 Uma Gupta Introduction to Information Systems 2000 by Prentice Hall. 3-1 Computer Hardware
2000 by Prentice Hall.3-2 Learning Objectives After studying this chapter, you will be able to: Discuss the fundamentals of data representation Describe the five hardware components in a computer system and their main functions Compare and contrast different types of computers according to size and speed: supercomputers, mainframes, minicomputers, workstations, and microcomputers Explain the process of buying a personal computer
2000 by Prentice Hall.3-3 Size and Time Units for Computers Amount of Memory Unit Byte Kilobyte (kB) Megabyte (MB) Gigabyte (GB) Terrabyte 8 bits 1,000 (10 3 ) bytes* 1,000,000 (10 6 ) bytes 1,000,000,000 (10 9 ) bytes 1,000,000,000,000 (10 12 ) bytes * This number is an approximation. The exact value is 1,024 bytes.
2000 by Prentice Hall.3-4 The Five Computer Components The central processor Secondary storage Input devices Output devices Communication devices
2000 by Prentice Hall.3-5 The Central Processor The central processor consists of two parts The central processing unit (CPU) –Arithmetic-log unit (ALU) –The control unit Primary storage –Random access memory (RAM) –Read-only memory (ROM) –Cache memory
2000 by Prentice Hall.3-6 Secondary Storage There are two main types of secondary storage Sequential –Magnetic tape Direct access –Magnetic disks –Redundant array of independent disks (RAID) –CD-ROM –Digital Versatile Disk (DVD)
2000 by Prentice Hall.3-7 Input Devices Input devices are the devices through which a computer accepts data Touch screens Voice-recognition systems Optical character reader (OCR)
2000 by Prentice Hall.3-8 Output Devices An output device is any device that helps the user to view the output of the computer Computer screen (video display terminal) Printers
2000 by Prentice Hall.3-9 Features of the Three Types of Printers Features Type of Printer Dot MatrixCheapest type of printer. Uses pins to press on a ribbon to make characters. Noisiest type of printer. Higher-quality output than the dot matrix. Uses a nozzle to spray ink onto a page. Produces about 2 to 8 ppm. Can print documents in color. Quieter than a dot matrix printer, but more expensive to operate. Highest-quality output, comparable to magazine output. Quietest printer. Typically the most expensive printer. Produces 4 to 16 ppm or more. Inkjet Laser
2000 by Prentice Hall.3-10 Communication Devices Devices that allow users separated by distance and time to exchange documents, files, graphics, and other digital information.
2000 by Prentice Hall.3-11 Computers That Support Different Work-group Sizes Personal Information Systems Work-group Systems Enterprise-wide Systems PCs Laptops/Notebooks Hand-held Computers Pen-based Computers Midrange or Minicomputers Workstations Supercomputers Mainframes
2000 by Prentice Hall.3-12 Supercomputers Some of the fastest and largest computers available today are supercomputers Supercomputers have two common characteristics The ability to process instructions in parallel (parallel processing) The ability to automatically recover from failures (fault tolerance)
2000 by Prentice Hall.3-13 Mainframes Mainframes are frequently enterprise-wide systems and are ideal for transaction processing, financial applications, payroll, investment analysis, and other applications that require extensive computations Many users can simultaneously use the mainframe One large disadvantage of the mainframe is that it is expensive to purchase, operate, and maintain
2000 by Prentice Hall.3-14 Midrange,or Minicomputers, and Workstations Although midrange computers are slower and often have less memory than mainframes, they are workhorses that can deliver excellent “bang for the buck” Workstations lie somewhere between midrange and personal computers They can be used by individuals or groups They are faster and more sophisticated than PCs They include numerous productivity tools that increase efficiency
2000 by Prentice Hall.3-15 Network Computers The network computer, also known as “thin clients” is a simplified version of a personal computer They are used mainly to access programs that reside on a company’s network or on the Internet Network computers are well suited for task-oriented jobs, such as data entry, order entry, and assembly line work Network computers function by downloading all applications from a central computer and obtaining and storing all data back on the central computer Network computers can offer cost efficiencies, but they rely heavily on network traffic and can cause bottlenecks
2000 by Prentice Hall.3-16 Microcomputers or Personal Computers (PCs) The memory size and processing capabilities of microcomputers are less than mainframes and midrange computers However, hardware technology advances have made the PC a compact and powerful machine A PC can be configured to meet the specific needs of users
2000 by Prentice Hall.3-17 Mobile Computers: Laptops, Notebooks, Handheld, and Pen-based These computers are battery operated so they can be used anytime, anywhere The portability of notebook and handheld computers has increased the productivity of many employees
2000 by Prentice Hall.3-18 A Comparison of Types of Mobile Computers Description Type LaptopFits on a user’s lap and is slightly larger than a notebook. Has full PC functionality with a reduced keypad and screen. Has a floppy drive. Has full PC functionality with a reduced keypad and screen and no floppy drive. Smaller than a laptop or notebook computer. Has a built-in monitor that can be operated from the palm of one’s hand so the keyboard and screen are smaller than a laptop. Often, the keyboard requires an electronic pen to input data. Uses an electronic writing pad and a light-sensitive electronic pen to input data. Can download text, photos, and other applications from PCs and transmit data via infrared rays; users input information on the LCD watch face that turns into a small keyboard. Notebook Handheld Pen-based Wrist
2000 by Prentice Hall.3-19 Six Technical Considerations in Buying a PC Monitors RAM Secondary Storage Clock Speed Processor Expansion Slots
2000 by Prentice Hall.3-20 Business Guidelines for Hardware Success Cost Is Only Part of the Story Many benefits resulting from information systems are intangible and tough to measure –increased productivity –improved decision making –faster customer service Don’t Compromise on Capacity and Reliability The motto “If it ain’t broke, don’t fix it” does not apply to hardware capacity and reliability
2000 by Prentice Hall.3-21 Business Guidelines for Hardware Success (cont.) Infrastructure, Infrastructure, Infrastructure Machines no longer work in isolation All business decisions should consider the technology infrastructure and IS professionals should be prepared to sell its importance to top management Support Is Crucial When there is a problem, users expect the problem to be fixed almost immediately Who will provide support? What is the nature of support? When will the support be provided?