Chapter 3 Software 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 Management Software Programs that manage hardware, software, and data resources of a system Four main types Operating systems Network management programs DBMS System Utilities

System Development Software 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