Chapter 4 Information Technology in Business Hardware 1

Chapter 4 Information Technology in Business: Hardware 1

The Central Tool of Modern Information Systems Four Basic Functions of Computers n Accept data n Process data n Store data and instructions n Output data 2

All computers have the same basic components. 3

The Central Tool of Modern Information Systems Organizations have moved from using large mainframes to using networked PCs. 4

Computers Communicating: Bits And Bytes Computer recognizes two states: on or off n Each on or off signal represents a bit (binary digit) 5

A Peek Inside the Computer Figure 4. 6 A look inside a computer 6

A Peek Inside the Computer The Central Processing Unit (CPU) n The brain of the computer n Microprocessor n Carries n Two signals that execute all processing Components: n Control unit n Arithmetic logic unit (ALU) 7

Microprocessor n Silicon chip embedded with transistors, or semiconductors letter D : 11000100 Schematic of how circuits on a chip would be open and closed to represent the letter D in EBCDIC (11000100) 8

–CPU’s execution of four functions: 1. Fetch 3. Execute What happens inside the CPU in one machine cycle executing the operation 7 + 5 2. Decode 4. Store 9

Machine Cycle n CPU’s execution of four functions: n Fetch n Decode n Execute n Store n Functions measured in small fractions of a second 10

TYPES OF MEMORY Memory n Internal Memory n Random access memory (RAM) n Read-only memory (ROM) n External Memory n Magnetic disks, magnetic tapes, optical discs 11

Computer Power n Clock rate (measured in cycles per second) n Amount of information the CPU can process per second 1 Mhz= 1 million Machine Cycle n Speed determined only by combination of both factors 12

Input Devices Keyboard Mouse, Trackball, and Track Pad Touch Screen Source Data Input Devices Imaging Speech Recognition 13

Output Devices Soft-Copy Output Devices Cathode-Ray Tube (CRT) Monitor n Flat-Panel Monitor n Speech Output n Hardcopy Output Devices Nonimpact Printers (most common) n Impact Printers n 14

External Storage Media Important Properties to Consider n Capacity n Speed n Cost 15

External Storage Media Magnetic Tapes Magnetic Disks Optical Discs (Compact Discs) Optical Tapes 16

External Storage Media 17

Classification of Computers Supercomputers n n The largest, most powerful, and most expensive Used by universities, research institutions, and large corporations Mainframe Computers n n Less powerful and less expensive than supercomputers Used by businesses with large amounts of data that need to be stored in a central computer 18

Classification of Computers Minicomputers Often used as the host computer in a network of smaller computers n Priced in the tens of thousands to a few hundred thousand dollars n Manufacturers: DEC (VAX), IBM (AS/400), and Hewlett-Packard n 19

Compatibility n Software and peripheral devices from one computer can be used with another computer. n In a networked environment, computers need to communicate to share databases and other computing resources. n In addition to power and cost, compatibility is an extremely important factor in purchasing decisions. 20

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

Considerations in Purchasing Hardware Factor What to Look For • Power Greater frequency and word size, larger • Expandability Greater number of board slots for additional RAM • Ports Greater number of ports for printer, external hard disk, communication devices and other peripherals • Ergonomics Greater comfort and safety • Compatibility Comparability with many other computers and peripheral devices, as swell as software packages • Footprint Smaller area • Support Availability of telephone and on-line support for troubleshooting • Warranty Longer warranty period • Cost Lower cost 22

SEQUENTIAL & PARALLEL PROCESSING SEQUENTIAL PARALLEL Program TASK 1 CPU RESULT Program CPU CPU TASK 1 TASK 2 TASK 3 RESULT TASK 2 CPU RESULT 23

CLIENT / SERVER CLIENT REQUESTS SERVER DATA, SERVICE USER INTERFACE DATA APPLICATION FUNCTION NETWORK RESOURCES 24