Chapter 3Software

• Two major types of software

• 1. Application Software - Programs designed for a specific purpose

• 2. System Software - Programs that manage the resources and operations of the computer system

Software Trends

• The trend in software is moving away from customized software designed for a specific company or organization

• Getting away from symbolic code

• Moving away from procedural programming languages

Software Trends

• Trend is towards the use of pre-written off-the-shelf software

• Use of natural style languages

• Visual interface, Object Oriented

Reasons for Current Trends

• Software developers have assembled software ‘suites’ that bundle several applications together

• Designed for ease of use and multiple functions

• Most recent trend is towards the offering of application software packages over the Internet

Application Software

• Two types of application software

• 1. General purpose - word processors, spreadsheets, database management programs, graphics, web browsers, email packages, groupware

• 2. Software suites combine several general purpose applications

The Suite Advantage

• Often called productivity suites

• Less expensive than separate purchases

• Most suites use a common graphical interface (same look , feel)

• Work together (import, export data)

Disadvantages of Suites

• Experts argue that most users never use the additional features

• Suites take up a lot of hard disk space and usually need high amounts of RAM

• Suites generally work slower than a stand alone application (because of integration)

Integrated Packages

• Integrated packages like Microsoft Works are a multifunction single application

• Disadvantage is the lack of features available in suites

Web Browsers

• Latest and greatest piece of application software

• Offer the ability to connect to the Internet and use Internet technology for additional purposes

• Fast becoming the universal piece of application software

Email Software

• Has changed the way people communicate

• Allows for messages to be sent to individual recipients or many at one time

• Can be secure message (password or encrypting)

• Allows for file attachment to message

• Can allow for remote access

Word Processors and Desktop Publishing

• Packages that allow for the creation, editing, revision, and printing of text based documents

• Can be converted easily to HTML format for web application

• Incorporate utilities such as grammar checkers, spelling checks, word usage, etc

Desktop Publishing

• Application software that allows for production of newsletters, books, manuals

• Allows for designing of page layout to work around non traditional page forms

• Allows for importing and formatting of images, graphics

Electronic Spreadsheets

• Program used for numerical analysis, planning, and modeling

• Can be used as database

• Very powerful business tool that can be easily customized by the end user

Database Management

• A database management application allows for the organized storage of data

• Allows for:– database development– database interrogation (queries)– database updates (acid functions)– protection of data– application development

Presentation Graphics

• Used to develop multimedia presentations

• Allow for the use of images, pictures, etc

• Easy to use

• Very effective teaching tool

• Can be used for web sites (must be transformed into HTML)

Hypermedia Technology

• Electronic documents that contain multiple forms of media

• Require use of specialized programming languages such as JAVA for development

• Creates links within HTML pages

Personal Information Managers

• Popular for end users

• Require no difficult programming

• Electronic calendar, appointment manager, schedule book

• Good for scheduling meetings within an organization

• May have an email link

Groupware

• Collaborative work software

• Central theme is to make group work possible and to remove barriers

• Allow for work folders where project documents are stored for access by project workers

System Software

• Manages the operation of the computer

• Link between hardware and application software

• Two main types of System Software– System management– System development

System ManagementSoftware

• Programs that manage hardware, software, and data resources of a system

• Four main types– Operating systems– Network management programs– DBMS– System Utilities

System DevelopmentSoftware

• Programs that aid in the development of custom software application

• Three basic forms– Translators and compilers– Programming tools– CASE (computer assisted software

engineering)

Operating System

• Single most important software package in a system

• Manages CPU

• Controls inputs, outputs, and system operation

• Directs system resources to maximize

• Allows for use of peripheral devices

Five Functions of Operating System

• Provides user interface

• Manages resources

• Manages tasks

• Manages files

• Provides for support (help screens) and utilities

User Interface

• Allows for communication and direction by the user to load programs, access and manage files

• Three main types:– Command driven– Menu driven– Graphical User Interface

User Interface

• The trend is towards graphical interfaces that make system commands appear simple

Resource Management

• The operating system controls programs that manage many system functions including:– CPU– Memory– Secondary storage– I/O devices

File Management

• The operating system controls the creation, storage, accessing of and management of files in the system

• Keeps track of the physical location of files on disks and other secondary storage devices

Task Management

• The operating system allows the computer to accomplish multiple tasks seemingly at the same time

• Multitasking

• Time sharing

Popular Operating Systems

• MS-DOS

• Windows 95/98/2000

• Windows NT

• OS/2

• UNIX

• LINUX

• Macintosh 7

System Development Software

• Programs are instruction sets

• Programs are written in many different programming languages

• There has been a definite evolution in programming languages

• There are five main categories of programming languages

Machine Language

• Basic level of programming language

• Written using binary code

• Very complicated and time consuming

• Very error prone

Assembler Languages

• Second generation of programming languages

• Usually called Symbolic languages

• Simpler to write than machine code

• Had to be used with a particular machine

High-Level Languages

• Third generation language

• COBOL, BASIC, FORTRAN

• Easier to learn because of orientation towards natural language

• Machine independent

• Must be compiled or translated into machine code by the software

4GL

• More conversational than others

• Simplifies programming tasks

• Use nonprocedural language

• Natural language

• Somewhat less flexible than some languages

Object Oriented Languages

• Links data elements and procedures together

• Languages include Visual Basic, C, C++, Java

• Easier to use

• Can use same object in multiple programs

HTML and Java

• HTML is a page defining language used for internet technology systems

• Java is an object oriented language

• Java was designed for real time uses

• Java code can contain small application programs within large programs called applets and/or JavaBeans

Language Translators

• Necessary to convert programming languages into machine code

• Assemblers - translate symbolic code

• Compilers - translate high level languages

• Interpreters - Execute instructions one level at a time