Information Systems Hardware

Chapter 2

Chapter Objectives

• Understand the important role of IS hardware in the success of modern organizations

• Describe key elements of IS hardware• List and describe the types of computers

used in organizations today• Explain how hardware has evolved and

where it is headed

The Importance of Information Systems Hardware

• Used in a rapidly changing, highly competitive global economy

• Relied upon for the exchange of real-time information

• Used on a daily basis for work, school, and fun

Key Elements of Information Systems Hardware

Output

Processing

Input

Input: How Information is Entered into an Information System

• The type of information determines how it is input– Text, numbers– Drawings, designs– Audio, video

Entering Original Text / Numbers

• Keyboard is most common entry device

• Advanced keyboards are ergonomically designed

Selecting and Pointing

• Mouse - most common pointing device

• Trackball

• Joysticks

• Touch screens

• Light pens

Entering Batch Data• Used for entering large amounts of routine

information

• Scanners– Convert printed text and images into digital data

• Text recognition software – Convert handwritten text to digital data

• Bar Code/Optical Character Readers– Use light to scan magnetic data

Audio and Video

• Microphone

• Digital cameras

• Video cameras

• Videocassette recorders

Processing: Transforming Inputs into Outputs

• All input must be converted into computer readable format

• Internal processing uses binary notation– Binary consists of a series of 0’s and 1’s– Each 0 or 1 is a bit– A combination of eight bits is a byte

• ASCII represents numbers and letters in binary code

Key Processing Elements

• Central Processing Unit (CPU)– Interprets and executes commands– Controls movement of data

• Primary storage– Current

• Secondary storage– Permanent

Figure 2.10Processor

ControlInstruct

PrimaryStorage

B

C

A

D

SecondaryStorage

Printer

CPU

Keyboard

Primary Storage: Storage for Current Information • Nonvolatile

– ROM (Read Only Memory)• Holds instructions to start up the computer

• Volatile– RAM (Random Access Memory)

• Stores data and program instructions the CPU is currently working on

– Cache Memory• Fast RAM for instructions queuing for immediate

processing by the CPU

Elements of Computer Storage

Name # of Bytes AbbreviationKilobyte 1,000 KBMegabyte 1,000,000 MBGigabyte 1,000,000,000 GBTerabyte 1,000,000,000,000 TB

Secondary Storage: Keeping Information for Later Use

• Permanent storage of data and programs– Magnetic tape– Floppy disks– Fixed disks– Compact discs– Optical disks

Magnetic Tape

• Same medium as audio cassette tapes

• Data stored by magnetically rearranging atoms on tape

• Uses sequential data access

• Primarily used for backing up large amounts of data

Files Files Files Files

Floppy Disks

• Small magnetic disks

• Transfer data between computers

• Use direct data access (random access)

• 2.5” disk holds 1.44 MB

• Iomega’s ZIP disk can store 100 MB

Fixed Disks• Several magnetic platters in a sealed

container

• Read/Write heads for each platter surface

• Greater storage capacity and data transfer rate than floppy disks

MultiplePlatters

Read/write

Heads

CD-ROM (Compact DiscRead-Only Memory)

• Uses the same technology as audio CD

• Uses direct access

• Holds 650MB

• Slower than fixed disk

• CD-R (CD-Recordable) drives available

Optical Disks

• Similar to CD-ROM technology

• May be rewritten many times

• Storage capacity of over 1 gigabyte (GB) on a single disk

• Disks and disk players relatively expensive

The Central Processing Unit: The Brain of the Computer

• Calculates and manipulates data

• Composed of millions of transistors

• Operates on electronic impulses

• Can perform more than a million instructions per second

Output: How Information is Displayed and Printed

• Output types are limited– Video output– Printer– Sound

Video Output

• Monitors– Most common video display– Uses a cathode ray tube (CRT)

• Liquid crystal display (LCD)– Used in portable computers

• Monitors embedded in many other devices

Paper-Based Displays

• Printers– Dot-matrix: form letters using a series of small

dots– Inkjet: spray ink on paper from a small

cartridge– Laser: use an electrostatic process to burn ink

to the paper

• Plotters– Transfer designs to drafting paper

Audio Output

• Uses small speakers and a sound card

• Translates digitized data into sound

Types of Computers

• Supercomputers

• Mainframes

• Minicomputers

• Workstations

• Microcomputers

Supercomputers

• The most powerful and expensive computers

• Contain numerous very fast processors that work in parallel

• Used by researchers and scientists to solve very complex problems

• Cost more than 1 million dollars

Mainframes

• The backbone of large corporate computing

• The only type of computer that existed 30 years ago

• Used for enterprise-wide computing

Minicomputers

• Scaled down versions of mainframes– Smaller– Less expensive

• Declining market due to faster and more powerful microcomputers

Workstations • The power of a minicomputer on a

desktop• Leaders in the market

– Silicon Graphics– Sun Micro Systems– DEC

• Process intensive applications– Computer-Aided Design (CAD)– Web Servers

Microcomputers

• Often called personal computers

• Desktop models

• Portable computers

• Most commonly used computing technology for knowledge workers

Evolution of Information Systems Hardware

• Shifts in computing eras facilitated by changes in computing technology

• Evolution marked by significant events creating four generations of hardware

The First Generation:Vacuum Tubes

• 1946 - 1958

• ENIAC: one of the first computers– 1946– Room-size with 18,000 vacuum tubes

• Replaced in 1950 by the UNIVAC

• Mainframe era begins

The Second Generation: Transistors

• 1958 -1964

• Transistors generate less heat

• Transistors are smaller, faster, and more reliable

• First transistors smaller than a dime

• Mainframe era continues

The Third Generation: Integrated Circuits (IC)

• 1964 -1990• Multiple transistors on a single chip • IBM 360 - First mainframe to use IC• DEC PDP-11 - First minicomputer • 1975 - Altair 8800 first microcomputer • 1981 - IBM introduced the PC• End of mainframe era, through mini era to

personal computing era

The Fourth Generation and Beyond

• 1990 - Present

• Radical new applications– Multimedia: the integration of voice, video

and data– Internet for video conferencing– End-user computing

The Future of Information System Hardware

• Will continue the trend of smaller, faster, cheaper and ubiquitous

• Virtual Reality

• Wearable Computing

• Smart Cards