Software Basics

Software Basics

The Ghost in the

Machine

4

 2001 Prentice Hall

4.2

Chapter Outline

•

Processing with Programs

•

Software Applications: Tools for
Users

•

System Software: The
Hardware-Software Connection

•

The User Interface: The
Human-Machine Connection

•

Tomorrow’s User Interfaces

“All
experience
shows
technological
changes
profoundly
transform
political and
social
relationships.”

John von Neumann

 2001 Prentice Hall

4.3

Processing with Programs

Software programs are:

– stored in memory
– a set of instructions that tell a

computer what to do

– designed to solve problems

 2001 Prentice Hall

4.4

Food for Thought

• Combine 2 slightly beaten eggs with 1 tsp

vanilla extract, ½ tsp cinnamon,  cup milk

• Dip 6 slices of bread in mixture
• Fry in small amount of butter until golden

brown

• Serve bread with maple syrup, sugar, or

tart jelly

Suzanne’s French Toast

Fantastique:

 2001 Prentice Hall

4.5

A Fast, Stupid Machine

Computers:

– Have limited capabilities
– Can only do basic

mathematics and logical
comparisons

– Must be instructed with

programs what to do

 2001 Prentice Hall

4.6

The Language of

Computers

• Programmers begin with an algorithm,

which is:

– A set of step-by-step instructions (written in

a natural language, e.g., English)

• Algorithms are ambiguous, error-prone

generalities

• Algorithms are translated into the

vocabulary of a programming language

 2001 Prentice Hall

4.7

Programming Languages

Bridge the gap

Human

language

Numeric code

COBOL, BASIC, and C+

+

 2001 Prentice Hall

4.8

Software Applications:

Tools for Users

Software applications include:

–

Consumer software

–

Integrated software

–

Vertical-market and custom software

 2001 Prentice Hall

4.9

Consumer Applications

• Consumer software differs from other

types (music CDs, videos, etc.) based
on:

–

Documentation

–

Upgrade options

–

Compatibility

–

Warranty

–

Extent of ownership/license

 2001 Prentice Hall

4.10

Documentation

Documentation

includes:

– Printed

tutorial

and

reference manuals

that explain how to use the software

–

On-line manuals

and

help screens

which offer immediate help to the user

 2001 Prentice Hall

4.11

Upgrades

• Newer releases often have additional

features and fewer bugs

• Upgrades allow you to pay a fee to

get the latest software version

 2001 Prentice Hall

4.12

Compatibility

• Compatibility

allows software to

function properly

with the hardware,

operating system,

and peripherals

• Programs written

for one type of

computer system

may not work on

another

 2001 Prentice Hall

4.13

Warranty

• Software manufacturers limit their

liability for software problems by
selling their software “as is”

• Error-free software does not exist

Buyer Beware!

 2001 Prentice Hall

4.14

Ownership/Licensing

• Three categories:

–

Purchased

software grants you a license to

use the software as the software company
tells you

–

Shareware

software is free for the trying,

but a nominal fee is to be paid to the
programmer if you continue to use it

–

Public domain

software is legally free and

cannot be owned or licensed

 2001 Prentice Hall

4.15

Integrated Applications and

Suites:

Software Bundles

• Multipurpose software includes

most of these modules:

– Word processing
– Database
– Spreadsheet
– Graphics
– Telecommunications

 2001 Prentice Hall

4.16

Integrated Software:

Advantages

•

Costs less

than buying the

applications individually

• Data is

easily transferred

between modules

• Commands used in each

module are usually the same

• Usually there is a

seamless

integration

of the modules

 2001 Prentice Hall

4.17

Vertical-Market and

Custom Software

• Job-specific software:

– Medical billings
– Library cataloging

–

Restaurant management

–

Single-client software needs

 2001 Prentice Hall

4.18

What the Operating System

Does

• The operating system controls:

– Communication with peripherals
– Coordination of concurrent processing
– Memory management
– Monitoring of resources and security
– Management of programs and data
– Coordinating network communications

 2001 Prentice Hall

4.19

Utility Programs

– repairing damaged files
– making it easy for users to copy files

from one storage device to another

– translating files so different

software can read them

– guarding against viruses

Utility software controls tasks such

as:

 2001 Prentice Hall

4.20

Where the Operating System

Lives

• Others include only part

of it in ROM

– The remaining system is

loaded into memory
(booting)

• Most of the time it

works behind the scenes

• Some computers store

their operating system

in ROM

 2001 Prentice Hall

4.21

The User Interface:

The Human-Machine Connection

The user interface is what

the user sees on the screen

Two major user interface

types:

–

Character-based

interface

–

Graphical user

interface (GUI)

 2001 Prentice Hall

4.22

A Character-Based Interface:

MS-DOS

• This is a disk operating system in

which the user interacts using
characters

– letters
– numbers
– symbols

 2001 Prentice Hall

4.23

A Character-Based User

Interface:

MS-DOS

• MS-DOS™ is the most widely used

general-purpose operating system

• Features include:

– Command-line interface (commands

are typed)

– Menu-driven interface (commands are

chosen from on-screen lists)

 2001 Prentice Hall

4.24

Graphical User Interfaces:

Macintosh

• This is a disk operating system in

which the user interacts with the
computer by using a pointing device
(e.g. a mouse)

• As early as 1984, the

Macintosh™ computer
was designed with this
interface in mind

 2001 Prentice Hall

4.25

Graphical User Interfaces:

Windows

• Windows 95

and 98 are
similar in many
ways to the
Mac OS

• Several versions

of Windows exist
for business and
home users

 2001 Prentice Hall

4.26

Why WIMP Won

W

indows,

I

cons,

M

enus, and

P

ointing devices

• They’re intuitive
• They’re consistent
• They’re forgiving
• They’re protective
• They’re flexible

 2001 Prentice Hall

4.27

Multiple User Operating

Systems: UNIX and Linux

•

UNIX

was developed at Bell Labs

before personal computers were
available

•

Linux

was created by Linus Torvalds

and continues to be a work-in-progress

– Linux is free for anyone to use or improve

 2001 Prentice Hall

4.28

•

UNIX

remains a dominant Internet

operating system for Internet servers.

Multiple User Operating

Systems: UNIX and Linux

• These systems allow a timesharing

computer to communicate with

several other computers or terminals

at once.

 2001 Prentice Hall

4.29

Hardware & Software

Platforms

• Windows 9x(ME)

• Windows 2000

• Windows CE

• Palm OS

• IBM’s OS/2

• Mac OS/9

• Mac OS/X

• UNIX & Linux

• BeOS

 2001 Prentice Hall

4.30

Rules of Thumb

Consumer Concepts

Before you buy:

– Join a user group or

talk with other

computer

and software owners

– Allow for “extras”

– Determine what you

can afford

 2001 Prentice Hall

4.31

Rules of Thumb:

Consumer Concepts

• What kind of tasks

you will be doing

• If your computer can

be customized to fit

your needs (such as

video editing)

• How much computer

power you need

Consider:

• If the processor can

handle your
demands

• If you will be able to

upgrade

 2001 Prentice Hall

4.32

Rules of Thumb:

Consumer Concepts

• If you need a high-

speed modem or
network connection

• Whether portability or

permanent connection
of peripherals is
important

• Which kind of user

interface will help you
do your work easier

Consider:

• If you should have the

same machine as
those you work with

• If you are buying from

a reputable company

• What kind of support is

available

 2001 Prentice Hall

4.33

Tomorrow’s User

Interfaces

– Make individual applications

obsolete

– Support natural languages

(talk to the machine and it

talks back)

– Include artificial intelligence

and agents that fit our needs

– Be based on virtual reality

(data in three-dimensional

physical space)

Future interfaces will probably: