Software: Systems & Application Software Chapter 4.

Software: Systems & Application

Software

Chapter 4

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Software basics

Software is a critical piece of making computers perform

Businesses typically spend more on software than hardware

Computer programs are sequences of instructions for the computer

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Two broad classes of Software

Systems Software Set of programs that coordinate activities & functions

of the hardware & various other programs Application Software

Programs that help users solve particular computing problems

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Software classified by “sphere of influence”

Personal Information Software: Systems that serve the needs of an individual user (e.g., wordprocessors, databases, spreadsheets)Workgroup Software: Systems that support two or more people who work together to achieve a common goal (e.g., group scheduling, conferencing)Enterprise Software: Systems that support the firm in its interaction with its environment (e.g., order entry, billing)

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Software Issues & Trends

Software Licensing Protection by software vendors to prevent

unauthorized use Software Upgrades

A revised version of software that usually includes fixes of known problems, plus enhancements to existing capabilities

Global Software Support Software that is distributed around the globe

may require unique support mechanisms due to local political & economic conditions

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Role of Systems Software

Role of Systems Software An interface or buffer between application

software & hardware Operating System

Controls the hardware & acts as an interface with application programs

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Operating System Functions

Perform common computer hardware functions Provide a user interface Provide a degree of hardware independence Manage system memory Manage processing tasks Provide networking capability Control access to system resources Manage files

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User Interfaces

User Interface A function of the operating system that allows

individuals to access & command the computer Command-Based User Interface

Requires text commands to perform basic activities Menu-Based User Interface

Requires pointing to menus & clicking on command Graphical User Interface (GUI)

Uses pictures (icons) & menus displayed on the screen to send commands to the computer system

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Software Concepts (1)

Hardware Independence Operating systems provide hardware

independence for application software The application software interfaces with

the operating system which interfaces with the hardware

OS

Hardware

Application

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Software Concepts (2)

Memory Management Controls how memory is accessed & maximizes available memory & storage

Virtual Memory Memory that allocates space in secondary storage to supplement the immediate, functional memory capacity of RAM

Paging A function of virtual memory that allows the computer to store currently needed pages in RAM while the rest of these

programs wait in secondary storage

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Software Concepts (3)

Multitasking A processing activity that allows a user to run more

than one application at the same time Multithreading

A processing activity that is basically multitasking within a single application

Time-sharing A processing activity that allows more than one person

to use a computer system at the same time

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Software Concepts (4)

Network capability Aids in connecting the computer to a network

Access to system resources Provides security for unauthorized access

File management Ensures that files in secondary storage are available when

needed & are protected against unauthorized usage Utility Programs

Merge & sort sets of data, keep track of computer jobs being run, compress files of data before they are stored or transmitted over a network, & perform other important tasks

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Types of Application Software

Proprietary Software Designed to solve a unique & specific problem Can be developed in-house or developed under

contract by an outside software provider Customized Software

Blend of in-house & external development Off-The-Shelf Software

An existing software program that can be used without considerable changes expected

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Personal Application Software

Word Processing Program Assistance in formulating, formatting, & printing documents such

as letters, memos, & papers Spreadsheet Program

Built-in functions for statistical, financial, logical, database, graphics, & data & time calculations

Database Program Stores, manipulates, & retrieves data

Software Suite Collection of personal productivity software such as word

processor, spreadsheet, & database Graphics Program

Assistance in making presentations, developing brochures, illustrations, etc.

On-Line Services Provide access to various information resources

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Object Linking & Embedding

Object Linking & Embedding (OLE) allows user to copy text/graphics from one document to another or to embed text/graphics from one program into another program/document Server Application supplies objects user places in other

applications Client application accepts objects from other applications Copy copies data from one application & places it in

another Link is used when user wants changes made to the server

object to appear automatically in all linked client objects Embed is used when user wants an object to become part of

the client document

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Workgroup Application Software

GroupWare Helps groups of people work together more efficiently

& effectively Collaborative Computing Software

Helps teams of people work together toward a common goal

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Enterprise Software

Enterprise Application Software Benefits the entire organization (e.g., accounts

receivable, accounts payable, general ledger, order entry, etc.)

Enterprise Resource Planning (ERP) A set of integrated programs that manage a company’s

vital business operations for an entire multi-site, global organization (e..g., SAP, PeopleSoft, J.D. Edwards, Oracle, etc.)

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Programming Languages (1)

Machine Language The first generation programming language A low-level language because it involves a basic

coding scheme using the binary symbols 1 & 0 Assembly Language

Second generation language Replaced binary digits with symbols programmers

could more easily understand Third Generation Languages

Continued trend to more symbolic code (e.g., COBOL, FORTRAN)

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More Programming Languages

Fourth Generation Languages (4GLs) Less procedural & even more English-like than third-generation languages (e.g.,

FOCUS) Query Languages

Ask the computer questions in English-like sentences (aka database query languages) Structured Query Language (SQL)

Standardized query language used to perform database queries & manipulations Most modern database management system applications use or support SQL

Fifth-Generation Languages Combines rule-based code generation, component management, visual programming

techniques, & reuse management

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Object Oriented Languages(Figure 4.17)

Object Oriented Languages: Small Talk, C++, Java

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Object Oriented Languages

Object-Oriented Languages allow interaction of programming objects, including data elements & the actions that will be performed on them Encapsulation: The process of grouping items into an object Polymorphism: A process allowing the programmer to develop

one routine or set of activities that will operate on multiple objects

Inheritance: Property used to describe objects in a group of objects taking on characteristics of other objects in the same group or class of objects

Reusable Code: The instruction code within an object that can be reused in different programs for a variety of applications

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Visual Programming Languages

Visual Programming Languages Use a mouse, icons, or symbols on the screen & pull-down menus to develop programs Examples: Visual Basic, Visual C++, PC COBOL

Knowledge-based Management Approach User tells the computer what he/she wants the computer to do rather than how to do

the job

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Language Translation

Language translator: Systems software that converts a programmer’s source code into its equivalent in machine language Interpreter: A language translator that translates one

program statement at a time into machine code Compiler: A language translator that converts a

complete program into machine language to produce a program that the computer can process in its entirety

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Case

Gap uses object-oriented programming pp. 184-185

Next Class Chapter 5 - Organizing data & information Case: US West - Data warehousing