Managing information technology
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Managing Information Technology. CHAPTER 3 COMPUTER SOFTWARE. EVOLUTION OF COMPUTER PROGRAMMING. First and Second Generation Languages. Machine language (1GL) Each instruction must be expressed in unique form for a particular computer Complete program consists of thousands of instructions

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Managing Information Technology

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Managing information technology

Managing Information Technology

CHAPTER 3COMPUTER SOFTWARE


Evolution of computer programming

EVOLUTION OF COMPUTER PROGRAMMING

First and Second Generation Languages

  • Machine language (1GL)

    • Each instruction must be expressed in unique form for a particular computer

    • Complete program consists of thousands of instructions

    • Programming is a tedious, time-consuming process

  • Assembly languages (2GL)

    • Easily remembered mnemonic operation codes substituted for machine language operation codes

    • Assembler used to convert mnemonic codes to machine language


Evolution of computer programming1

EVOLUTION OF COMPUTER PROGRAMMING

First and Second Generation Languages


Evolution of computer programming2

EVOLUTION OF COMPUTER PROGRAMMING

Third and Fourth Generation Languages

  • Procedural languages (3GL)

    • Typically machine independent

    • Express a step-by-step procedure devised by the programmer

    • Must be compiled or interpreted (translated into machine language)

    • Include FORTRAN, COBOL, BASIC, PL/1, PASCAL, ADA, and C


Evolution of computer programming3

EVOLUTION OF COMPUTER PROGRAMMING

Third and Fourth Generation Languages


Evolution of computer programming4

EVOLUTION OF COMPUTER PROGRAMMING

Third and Fourth Generation Languages

  • Nonprocedural languages (4GL)

    • Also referred to as productivity languages

    • Use more English-like statements for program instructions

    • Easier to use, write, and less error-prone

    • Use a built-in interpreter to convert to machine language

    • Take much longer to execute than 3GLs

    • Include FOCUS, CA-Ramis, IFPS, and SAS


Evolution of computer programming5

EVOLUTION OF COMPUTER PROGRAMMING

Third and Fourth Generation Languages


Evolution of computer programming6

EVOLUTION OF COMPUTER PROGRAMMING

Third and Fourth Generation Languages

  • Object-oriented languages

    • 3GLs with some 4GL features

    • Built on idea of embedding procedures (methods) in objects, and putting objects together to create an application

    • Include Smalltalk, C++, Java, and Visual Basic


Key types of software

KEY TYPES OF SOFTWARE

  • Applications software

  • Support software


Applications software

APPLICATIONS SOFTWARE

  • Programs written to accomplish particular tasks

  • Many different types of applications software

  • Standard applications products generally purchased from an outside source

  • Applications unique to the organization generally developed internally

  • Personal productivity software most important to managers


Applications software1

APPLICATIONS SOFTWARE

Examples of Application Software

  • Peachtree accounting software

    • Commercial accounting package for smaller businesses

    • Includes general ledger, accounts receivable, accounts payable, inventory, payroll, time and billing, job costing, fixed asset accounting, and analysis and reporting tools

    • $500 for single-user version


Applications software2

APPLICATIONS SOFTWARE

Examples of Application Software

  • Sage Accpac 200 ERP

    • Modular financial management systems for midsized businesses

    • Web-based, so only a Web browser is needed to access the application

    • System Manager module manages security, ensures data integrity, handles bank reconciliation and tax processing, and allows for customized reports

    • Several other modules available as well


Applications software3

APPLICATIONS SOFTWARE

Personal Productivity Software

  • Word processing

    • Used to create documents for printing

    • Most popular is Microsoft Word

    • Others include Corel WordPerfect, Lotus WordPro, and Sun’s StarOffice Writer

    • All employ WYSIWYG


Applications software4

APPLICATIONS SOFTWARE

Personal Productivity Software

  • Spreadsheets

    • Used to create applications that fit a row-column format

    • Most popular is Microsoft Excel

    • Others include Lotus 1-2-3 and Corel Quattro Pro

    • All employ rows, columns, cells, formulas, and “what-if” analysis


Applications software5

APPLICATIONS SOFTWARE

Personal Productivity Software

  • Database management systems

    • Used to create databases similar to those on larger machines

    • Most popular is Microsoft Access

    • Others include FileMaker Pro, Corel Paradox, and Lotus Approach

    • All employ a relational data model


Applications software6

APPLICATIONS SOFTWARE

Personal Productivity Software

  • Presentation graphics

    • Used to create largely textual business presentations

    • Most popular is Microsoft PowerPoint

    • Others include Corel Presentations and Lotus Freelance Graphics

    • All allow embedding of clip art, photos, graphs, and other media


Applications software7

APPLICATIONS SOFTWARE

Personal Productivity Software

  • Web browsers

    • Used to access information on the Web

    • Requires ISP service to link PC to Internet

    • Create documents for printing

    • Most popular are Internet Explorer and Firefox… both free!

    • Both employ standard hypertext-based approach (way to link text and media objects to each other)

    • Pull technology: browser requests a Web page before it is sent to desktop

    • Push technology: data sent to client without requesting it (such as e-mail)


Applications software8

APPLICATIONS SOFTWARE

Personal Productivity Software

  • Electronic mail

    • Preferred way of communicating in business today

    • Easy to use and precise

  • Groupware

    • Incorporates e-mail and other productivity features, such as calendaring, scheduling, and document sharing


Support software

SUPPORT SOFTWARE

  • Provides computing environment that is easy and efficient for humans to use

  • Enables applications programs to be carried out

  • Ensures that computer hardware and software are used efficiently

  • Almost always purchased from a hardware vendor or software house


Support software1

SUPPORT SOFTWARE

Operating System

  • Most important type of support software

  • Complex program that controls operation of computer hardware and coordinates other software

  • User communicates with operating system software to control hardware and software resources

  • Communication made easier with a graphical user interface (GUI) feature


Support software2

SUPPORT SOFTWARE

Operating System


Support software3

SUPPORT SOFTWARE

Operating System

  • Job control language (JCL): keyed instructions from the computer user to communicate with the operating system

  • Multiprogramming: employed on larger machines to overlap input and output operations with processing time, keeping the CPU busy and speeding up execution

  • Multitasking: similar to multiprogramming, but employed on microcomputers

  • Multithreading: similar to multitasking, but multiple threads within the same program are overlapped


Support software4

SUPPORT SOFTWARE

Operating System

  • Virtual Memory:

    • Concerned with management of main memory

    • Makes it appear that an unlimited amount of memory is available

    • Permits multiprogramming to operate more efficiently

  • Multiprocessing: work that takes place when two or more CPUs are installed on same computer system


Support software5

SUPPORT SOFTWARE

Operating System

  • Sources of operating systems

    • Proprietary systems: most popular type of operating systems, written for a particular computer hardware configuration

      • Microcomputers: MS-DOS, PC-DOS, Windows XP

      • Midrange systems: OS/400

      • Large systems: VM and MVS

    • Open systems: not tied to any particular computer system or hardware manufacturer – will run on virtually any computer system

      • Examples: UNIX and Linux


Support software6

SUPPORT SOFTWARE

Operating System

  • Network operating systems (NOS)

    • Software running on a server that manages network resources and controls the operation of a network

    • Enhanced operating system that allows for:

      • Sharing disk drives and printers

      • Handling server side of client/server applications

    • Major players include:

      • UNIX and Linux

      • Microsoft Windows NT, 2000 Server, 2003 Server

      • Novell NetWare


Support software7

SUPPORT SOFTWARE

Third Generation Languages

  • Procedural languages (3GL)

    • Require logical thinking

    • Entail development of a detailed step-by-step procedure

    • Can be developed using structured programming


Support software8

SUPPORT SOFTWARE

Third Generation Languages


Support software9

SUPPORT SOFTWARE

Third Generation Languages

  • Structured programs

    • Divided into modules, where each has one entry and one exit point

    • Advantages

      • Program logic easier to follow

      • Maintenance and correction easier and faster

      • Do not use GO TO logic


Support software10

SUPPORT SOFTWARE

Third Generation Languages

  • Most popular procedural languages

    • BASIC

    • C

    • COBOL

  • Other procedural languages

    • FORTRAN

    • PL/1

    • PASCAL

    • ADA


Support software11

SUPPORT SOFTWARE

Third Generation Languages - BASIC


Support software12

SUPPORT SOFTWARE

Third Generation Languages - COBOL


Support software13

SUPPORT SOFTWARE

Fourth Generation Languages

  • Nonprocedural languages

    • Use very high-level instructions

    • Require fewer instructions

    • Easier to write, modify, and understand

    • Example: FOCUS


Support software14

SUPPORT SOFTWARE

Fourth Generation Languages - FOCUS


Support software15

SUPPORT SOFTWARE

Markup Languages

  • Employ tags to “mark up” documents

  • HTML

    • Used to create Web pages

    • Consists of special tags that tell the Web browser how to display various elements on a Web page (e.g., bold-faced or italic text, image location, links to other Web pages)

  • XML

    • Used to facilitate data interchange among Web applications

    • Metalanguage consisting of tags that identify particular data elements


Support software16

SUPPORT SOFTWARE

Object-Oriented Programming

  • Requires more computing power

  • Has built-in GUI

  • Neither 3GL nor 4GL … new paradigm

  • Creates objects only once and stores for reuse

  • Object examples:

    • Text box, check box, entity in an organization

  • Languages:

    • Smalltalk, C++, Java, Visual Basic.NET


Support software17

SUPPORT SOFTWARE

Object-Oriented Programming - Java


Support software18

SUPPORT SOFTWARE

Languages for Developing Web Applications

  • HTML form is the most common user interface encountered by users

  • Server-side programming languages include:

    • Perl

    • Java Servlets and Java Server Pages

    • Microsoft Active Server Pages (ASP, ASP.NET)

    • ColdFusion


Support software19

SUPPORT SOFTWARE

Languages for Developing Web Applications


Support software20

SUPPORT SOFTWARE

Database Management Systems

  • Support software used to create, manage, and protect organizational data

  • Database: shared collection of logically related data organized to meet organizational needs

  • Five basic architectures:

    • Hierarchical

      • Data are arranged in a top-down organization chart fashion

      • Example: IBM Information Management System (IMS)


Support software21

SUPPORT SOFTWARE

Database Management Systems

  • Five basic architectures:

    • Network

      • Data are arranged like cities on a highway system, often with several paths from one piece of data to another

      • Example: Computer Associates Advantage CA-IDMS

    • Relational

      • Most common type

      • Data arranged in simple tables

      • Records related by storing common data in each associated table

      • Examples: Microsoft Access and SQL Server, Paradox, DB2, and Ingres


Support software22

SUPPORT SOFTWARE

Database Management Systems

  • Five basic architectures:

    • Object-oriented

      • Data can be graphics, video, and sound as well as simpler data types

      • Attributes and methods are encapsulated in object classes, and relationships between classes can be shown by nesting one class within another

      • Examples: Versant Object Database, Progress ObjectStore, and Objectivity/DB

    • Object-relational

      • Hybrid approach that can handle complex data types with the simplicity of the relational model

      • Examples: Oracle, IBM’s DB2 and Cloudscape, and FFE Software’s FirstSQL/J


Support software23

SUPPORT SOFTWARE

File Organizations

  • Sequential: arranges records physically adjacent and in order by some (usually unique) sort key

  • Direct: uses key for records placed so that they are rapidly accessed from DASDs


Support software24

SUPPORT SOFTWARE

File Organizations

  • Indexed

    • Compromise between sequential and direct

    • Record keys only arranged in sequence in a separate table, along with location of rest of data associated with that key

    • Popular types include ISAM and VSAM


Support software25

SUPPORT SOFTWARE

CASE Tools

  • Computer-aided software engineering (CASE)

  • Collection of software tools to help automate all phases of the software development life cycle

  • Growth slower than anticipated

  • Radically changed nature of systems analyst and programmer jobs


Support software26

SUPPORT SOFTWARE

CASE Tools

  • Recent surge in CASE tools for Unified Modeling Language (UML)

    • UML is a general-purpose notational language for specifying and visualizing complex software, especially large, object-oriented projects

    • Examples of UML-base CASE tools

      • IBM’s Rational Rose

      • Borland’s Together

      • Sybase’s PowerDesigner


Support software27

SUPPORT SOFTWARE

Communications Interface Software

  • Large computers

    • Need to control workstations and terminals

    • Example software: IBM’s CICS, TSO, and CMS

  • Increasingly important with growth of LANs and WANs

  • Web browsers: enable users to look around, or “browse,” the Internet

  • Telnet: permits user to log into remote computer

  • File Transfer Protocol (FTP): used to transfer files from one computer system to another


The changing nature of software

THE CHANGING NATURE OF SOFTWARE

  • Less concern with machine efficiency

  • More purchased applications, and, conversely, more use of open source support software, such as Linux

  • More programming using object-oriented languages

  • More emphasis on applications that run on intranets and the Internet

  • More user development

  • More use of personal productivity software on microcomputers


The software component of the information systems industry

THE SOFTWARE COMPONENT OF THE INFORMATION SYSTEMS INDUSTRY

Major Groups

  • Hardware manufacturers

    • IBM, Hewlett-Packard, Sun Microsystems, Hitachi, and Fujitsu

  • Software houses

    • Microsoft, Oracle, SAP, Computer Associates, and Symantec

  • Consulting firms

    • PricewaterhouseCoopers Consulting (bought by IBM)


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