Chapter 4

Information Technology in Business:

Hardware

2

The Central Tool of Modern Information Systems

Four Basic Functions of ComputersAccept dataProcess dataStore data and instructionsOutput data

3All computers have the same basic components.

4Organizations have moved from using large mainframes to using networked PCs.

The Central Tool of Modern Information Systems

5

Computers Communicating: Bits And Bytes

Computer recognizes two states: on or off

Each on or off signal represents a bit (binary digit)

6

A Peek Inside the Computer

Figure 4.6 A look inside a computer

7

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 unitArithmetic logic unit (ALU)

8

Microprocessor

Microprocessor 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)

9What happens inside the CPU in one machine cycle executing the operation 7 + 5

–CPU’s execution of four functions:

1.Fetch 2. Decode 3.Execute 4. Store

10

Machine Cycle

Machine Cycle CPU’s execution of four functions:

Fetch Decode Execute Store

Functions measured in small fractions of a second

11

Memory Internal Memory

Random access memory (RAM) Read-only memory (ROM)

External Memory Magnetic disks, magnetic tapes, optical discs

TYPES OF MEMORY

12

Computer Power Clock rate (measured in cycles per second)

Amount of information the CPU can process per second

1Mhz= 1 million Machine Cycle

Speed determined only by combination of both factors

Computer Power

13

Input Devices

Keyboard

Mouse, Trackball, and Track Pad

Touch Screen

Source Data Input Devices

Imaging

Speech Recognition

14

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

15

External Storage Media

Important Properties to ConsiderCapacitySpeedCost

16

External Storage Media

Magnetic Tapes

Magnetic Disks

Optical Discs (Compact Discs)

Optical Tapes

17

External Storage Media

18

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

19

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

20

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.

21

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

22

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

Considerations in Purchasing Hardware

23

SEQUENTIAL & PARALLEL PROCESSING

SEQUENTIAL PARALLELSEQUENTIAL PARALLEL

TASK 1

RESULT

TASK 2

RESULT

ProgramProgram

CPUCPU

ProgramProgram

CPUCPU

ProgramProgram

CPUCPUTASK 2TASK 2

CPUCPUTASK 3TASK 3

CPUCPUTASK 1TASK 1

RESULTRESULT

24

CLIENT SERVERREQUESTS

DATA, SERVICE

USER INTERFACE

APPLICATION

FUNCTION

DATA

APPLICATION FUNCTION

NETWORK RESOURCES

CLIENT / SERVER