2 Learning Objectives When you finish this chapter, you will:  Recognize major components of an electronic computer.  Understand how the different components work.  Know the functions of peripheral equipment.

3 Learning Objectives  Be able to classify computers into major categories, and identify their strengths and weaknesses.  Be able to identify and evaluate key criteria when deciding what computers to purchase.  Know the controversy regarding the health hazards of computers.  Recognize how to evaluate hardware so that you can harness it to improve managerial processes.

4 The Central Tool of Modern Information Systems Four Basic Functions of Computers  Accept data  Process data  Store data and instructions  Output data

5 The Central Tool of Modern Information Systems Figure 4.1 All computers have the same basic components.

6 The Central Tool of Modern Information Systems Figure 4.2 Organizations have moved from using large mainframes to using networked PCs.

7 The Central Tool of Modern Information Systems Figure 4.3 A timeline of computing

8 The Central Tool of Modern Information Systems Figure 4.3 (continued) A timeline of computing

9 Computers Communicating: Bits And Bytes Computer recognizes two states: on or off  Each on or off signal represents a bit (binary digit) Encoding Schemes  Representation of symbols by unique strings of bits Counting Bases  Decimal system is “base 10”  Binary system is “base 2”  Used by computers

10 Computers Communicating: Bits And Bytes Figure 4.4 Binary encoding schemes

11 A Peek Inside the Computer Figure 4.5 A look inside a computer

12 A Peek Inside the Computer The Central Processing Unit (CPU)  The brain of the computer  Microprocessor  Carries signals that execute all processing  Two Components:  Control unit  Arithmetic logic unit (ALU)

13 A Peek Inside the Computer Microprocessor  Silicon chip embedded with transistors, or semiconductors Figure 4.6 Schematic of how circuits on a chip would be open and closed to represent the letter D in EBCDIC ( )

14 A Peek Inside the Computer Figure 4.7 What happens inside the CPU in one machine cycle executing the operation 7 + 5

15 A Peek Inside the Computer Machine Cycle  CPU’s execution of four functions:  Fetch  Decode  Execute  Store  Functions measured in small fractions of a second Figure 4.8 Computer time

16 A Peek Inside the Computer Memory  CPU Registers  Internal Memory  Random access memory (RAM)  Read-only memory (ROM)  External Memory  Magnetic disks, magnetic tapes, optical discs

17 A Peek Inside the Computer Computer Power  Clock rate (measured in cycles per second)  Amount of information the CPU can process per second  Speed determined only by combination of both factors

18 Input Devices Keyboard Mouse, Trackball, and Track Pad Touch Screen Source Data Input Devices Imaging Speech Recognition

19 Input Devices Figure 4.9 Banks use magnetic-ink character recognition (MICR) to automate their input procedures.

20 Output Devices Soft-Copy Output Devices  Cathode-Ray Tube (CRT) Monitor  Flat-Panel Monitor  Speech Output Hardcopy Output Devices  Nonimpact Printers (most common)  Impact Printers

21 Output Devices Figure 4.10 In an RGB monitor, the electron gun creates many different colors and hues from three primary colors: red, green, and blue.

22 External Storage Media Important Properties to Consider  Capacity  Speed  Cost

23 External Storage Media Magnetic Tapes Magnetic Disks Optical Discs (Compact Discs) Optical Tapes

24 External Storage Media Business Considerations of Storage Media  Trade-offs  Modes of Access  Sequential Access  Direct Access

25 External Storage Media Figure 4.11 Characteristics of storage media for business consideration

26 External Storage Media Figure 4.12 Sequential and random data organization

27 Classification of Computers 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

28 Classification of Computers Minicomputers  Often used as the host computer in a network of smaller computers  Priced in the tens of thousands to a few hundred thousand dollars  Manufacturers: DEC (VAX), IBM (AS/400), and Hewlett-Packard

29 Figure 4.13 PC sales continue to grow. Classification of Computers The Microcomputer Revolution Computers on the Go: Laptop and Handheld Computers

30 Classification of Computers Figure 4.14 Market shares of PC manufacturers

31 Classification of Computers Figure 4.15 Shipments of PCs, past and future (in millions of units)

32 Classification of Computers Figure 4.16 A PDA’s operating system is intelligent enough to turn rough drawings into neat ones or handwriting into text.

33 Classification of Computers Compatibility  Software and peripheral devices from one computer can be used with another computer.  In a networked environment, computers need to communicate to share databases and other computing resources.  In addition to power and cost, compatibility is an extremely important factor in purchasing decisions.

34 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  Vendor reliability, warranty policy, vendor support

35 Considerations in the Purchase of Hardware 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 CompatabilityCompatability with many other computers and peripheral devices, as swell as software packages FootprintSmaller area SupportAvailability of telephone and on-line support for troubleshooting WarrantyLonger warranty period Cost Lower cost Figure 4.17 Example of a hardware evaluation form

36 Ethical and Societal Issues Computers May Be Hazardous to Your Health Physical and Emotional Stress  General physical and emotional stress  Muscular-skeletal problems  Repetitive Stress Injuries (RSI)  Vision problems