1. Computer Software Chapter 4 Copyright © 2010 by the McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin

2. 4-2 Learning Objectives Describe several important trends occurring in computer software Give examples of several major types of application and system software Explain the purpose of several popular software packages for end user productivity and collaborative computing

3. 4-3 Learning Objectives Define and describe the functions of an operating system Describe the main uses of computer programming software, tools, and languages Describe the issues associated with open source software

4. 4-4 Types of Application & System Software

5. 4-5 General Purpose –Programs that perform common information processing jobs for end users –E.g., word processing, spreadsheet –Also call productivity packages Application-specific –Programs that support specific applications of end users –E.g., electronic commerce, customer relationship management, etc. Application Software (Functionality-based)

6. 4-6 Commercial Off-the-Shelf (COTS) –Many copies sold –Minimal changes beyond scheduled upgrades –Purchasers have no control over specifications, schedule, or evolution, and no access to source code or internal documentation –Product vendor retains the intellectual property rights of the software Custom –Software applications developed within an organization for use by that organization Application Software (Development-based)

7. 4-7 Application Software (Development-based) Open-source Software –Developers collaborate on the development of an application using programming standards which allow anyone to contribute to the software –As each developer completes a project, the application code becomes available and free to anyone who wants it

8. 4-8 Business Application Software Thousands of these packages support specific end-user applications Customer Relationship Management Enterprise Resource Planning Supply Chain Management Function-Specific Application Software Web-enabled electronic commerce

9. 4-9 Software Suites Most widely used productivity packages are bundled as software suites Advantages 1. Cost less than buying individual packages 2. All have similar GUI 3. Programs work well together Disadvantages 1. All features not used 2. Takes a lot of disk space (bloatware)

10. 4-10 Components of Top Software Suites

11. 4-11 Integrated Packages Integrated packages combine the functions of several programs into one package E.g., Microsoft Works, AppleWork Advantages 1. Many functions for lower price 2. Uses less disk space 3. Frequently pre- installed on PCs Disadvantages 1. Limited functionality

12. 4-12 Web Browsers (the universal client) Software that supports navigation through point-and-click, hyper-linked Web resources Becoming the universal platform from which end users launch… Information searches E-mail Multimedia file transfer Discussion groups Other Internet-based applications

13. 4-13 Search Engines Google, Ask Jeeves, Look Smart, Lycos, Overture, Yahoo! Browsers are used to gain access to Internet search engines Using search engines to find information has become an indispensable part of Internet, intranet, and extranet applications

14. 4-14 E-mail, Instant Messaging, Weblogs E-mail –Sending and receiving messages and attachments via the Internet, intranet, or extranet e.g. Microsoft Hotmail Instant messaging (IM) –Receive electronic messages instantly Weblog or blog –A personal website in dated log format –Updated with new information about a subject or range of subjects

15. 4-15 e.g. of a blog

16. 4-16 Word Processing/Desktop Publishing Word Processing –Create, edit, revise, and print attractive documents –Convert documents to HTML –E.g., Microsoft Word, Lotus WordPro, Corel WordPerfect Desktop Publishing –Produce printed materials that look professionally published –Brochures, manuals and books –E.g., Adobe PageMaker, Microsoft Publisher, QuarkXPress

17. 4-17 Electronic Spreadsheets Used by virtually every business for analysis, planning, modeling Worksheet of rows and columns Can be stored on local computers or a network Requires designing format and developing the relationships (formulas) Most help you develop charts and graph displays of spreadsheet results Supports what-if questions

18. 4-18 Presentation Graphics Microsoft PowerPoint, Lotus Freelance, Corel Presentations Top packages can tailor files for transfer in HTML format to websites Convert numeric data into graphics Common presentation graphics packages… Are used to create multimedia presentations of graphics, photos, animation, video Helps emphasis things

19. 4-19 Personal Information Managers Manages schedules, appointments, tasks Most have ability to access the Web and e-mail Stores information about clients Some support team collaboration by sharing information with other PIM users e.g., Lotus Organizer, Microsoft Outlook Software for end user productivity and collaboration

20. 4-20 Personal Information Managers

21. 4-21 Groupware Software that helps workgroups collaborate on group assignments –E-mail, discussion groups, databases, audio, and video conferencing –E.g., Lotus Notes, Novell GroupWise, Microsoft Exchange –Rely on the internet, intranet and extranet to make collaboration possible. –Collaborative capabilities are being added to other software e.g. Excel –Windows SharePoint Services and WebSphere both allow teams to create websites for information sharing and document collaboration

22. 4-22 Software Alternatives Outsource software development and maintenance Application service providers (ASPs) –Companies that own, operate, and maintain application software and computer system resources –Use the application for a fee over the Internet –Advantage1: Pay-as-you-go, low cost of initial investment, less time. –Advantage2: Reduce IT infrastructure e.g. IT personnel –Use expected to accelerate

23. 4-23 ASP Example

24. 4-24 Cloud Computing Software and virtualized hardware resources are provided as a service over the Internet –No technology knowledge, expertise, or control needed –Often confused with grid computing –Pay-for-use avoids capital expenditures –Sharing “perishable and intangible” computer power improves utilization rates –Capacity can be scaled upward almost instantly –Immediate access to broad range of applications –Contracts can generally be terminated at any time

25. 4-25 Cloud Computing

26. 4-26 Cloud Computing

27. 4-27 Cloud Computing e.g. “SkyDrive”

28. 4-28 Cloud Computing

29. 4-29 Categories of System Software System Management Programs System Development Programs Manages hardware, software, network, and data resources of computer systems Operating systems, network management programs, database management systems, system utilities Helps users develop IS programs and procedures, and then prepare them for processing Includes language translators and editors, CASE, and programming tools

30. 4-30 Interface Between End Users & Computer

31. 4-31 Operating Systems Integrated system of programs that… Provides support services as the computer executes application programs Manages the operations of the CPU Controls the input/out, storage resources, and activities of the computer system The operating system must be loaded and activated before other tasks can be accomplished

32. 4-32 Operating Systems The primary purpose of an Operating System: 1- Maximize the productivity of a computer system 2- Minimizes the human intervention during processing

33. 4-33 Operating System Basic Functions Command-driven Menu-driven Graphical User Interfaces (GUI)

34. 4-34 Operating System Basic Functions User Interface: Allow communicating with the computer Resource Management Part of the operating system that manages the hardware and networking resources of a computer system –Includes CPU, memory, secondary storage devices, telecommunications, and input/output peripherals Common functions –Keeping track of where data and programs are stored –Subdividing memory; providing virtual memory capability File Management Part of the operating system that controls the creation, deletion, and access of files and programs –Keeps track of physical location of files on storage devices –Maintains directories of information about the location and characteristics of stored files

35. 4-35 Operating System Basic Functions Task Management Part of the operating system that manages the accomplishment of end user computing tasks –Controls which task gets access to the CPU, and for how long –Can interrupt the CPU at any time to substitute a higher priority task –Supports preemptive and cooperative multi-tasking and multi-processing 1- Multitasking: (multiprogramming or time-sharing): using only one CPU 2 Types:  A) Preemptive  B) Cooperative 2- Multiprocessing: using more than one CPU

36. 4-36 Popular Operating Systems Windows –GUI, multitasking, networking, multimedia –Microsoft’s operating system –NT, XP, 2003 –Different versions manage servers Standard, enterprise, data center, Web Unix –Multitasking, multi-user, network-managing –Portable - can run on mainframes, midrange, and PCs

37. 4-37 Popular Operating Systems Linux –Low-cost, powerful, reliable, Unix-like operating system –Open-source

38. 4-38 Open Source Software The basic idea –When programmers can read, redistribute, and modify source code, the software evolves –This can happen at astonishing speed –Produces better software than the traditional commercial (closed) model –The proprietary (commercial) approach to software development has hidden costs that often outweigh its benefits

39. 4-39 Open Source Software Open source software is not… –Shareware –Public domain software –Freeware –A viewer or reader made freely available without source code OSS… –Is copyrighted & distributed with license terms –Sometimes carries a fee for packaging, distribution, or support

40. 4-40 Examples of Open Source Software Open Office –Can be used for any purpose: domestic, commercial, educational, or public administration Mac OS X –Based on a form of UNIX –Advanced GUI –Supports multi-tasking and multimedia –Integrated Web browser, e-mail, instant messaging, search engine, digital media player, and more –Includes software development tools

41. 4-41 Application Virtualization A term for software technologies that improve portability, manageability, and compatibility of applications –Works by insulating applications from the underlying operating system Benefits –No need for multiple platforms for multiple applications –Energy savings from not having servers running at low capacity

42. 4-42 Application Virtualization e.g. (VMware)

43. 4-43 Other System Management Software Utilities –Miscellaneous housekeeping functions –Example: Norton utilities includes data backup, virus protection, data compression, etc. Performance Monitors –Programs that monitor and adjust computer system to keep them running efficiently Security Monitors –Monitor and control use of computer systems to prevent unauthorized use of resources

44. 4-44 Application Servers Provide an interface between an operating system and the application programs of users Middleware –Helps diverse software applications exchange data and work together more efficiently –E.g. web servers

45. 4-45 Programming Languages

46. 4-46 Machine Languages First Generation Languages The most basic of programming languages Strings of binary codes unique to each computer Requires specific knowledge of the internal operations of the CPU being used Must specify the storage location for every instruction and item of data used Difficult to work with, and error prone

47. 4-47 Assembler Languages Second Generation Languages Developed to reduce difficulties in writing machine language programs Uses assemblers to convert the programs into machine instructions Symbols used to represent operation codes and storage locations Alphabetic abbreviations, called mnemonics, and other symbols represent operation codes, storage locations, and data elements

48. 4-48 High-Level Languages Third Generation Languages Uses brief statements or arithmetic expressions Statements translated into machine language by compilers or interpreters Easier to learn and program, Less efficient than assembler language and requires greater translation time Machine independent Examples: BASIC, COBOL, FORTRAN

49. 4-49 Fourth-Generation Languages Variety of programming languages that are nonprocedural and conversational Programmers specify the result wanted; the computer determines the sequence of instructions that accomplish the result Simplifies the programming process Natural language; very close to English Sometimes called fifth-generation (5GLs)

50. 4-50 SQL (4GL)

51. 4-51 Object-Oriented Languages

52. 4-52 Object-Oriented Languages Combines data elements and the procedures that will be performed upon them into objects –E.g., data about a bank account and the procedures performed on it, such as interest calculations

53. 4-53 Object-Oriented Languages Easier to use and more efficient for graphics- oriented user interfaces Most widely used software development languages Reusable: can use an object from one application in another application Examples: Visual Basic, C++, Java Most object-oriented languages provide a GUI that supports visual programming

54. 4-54 Web Languages HTML A page description language that creates hypertext documents for the Web XML Describes Web page content by applying identifying tags or contextual labels to the data Java Object-oriented programming language that is simple, secure, and platform independent Java applets can be executed on any computer

55. 4-55 HTML e.g.

56. 4-56 XML e.g.

57. 4-57 Java Applet

58. 4-58 How Web Services Work Web services are software components that are: –Based on framework of Web and object- oriented standards and technology –Used to link the applications of different users and computing platforms via the Web

59. 4-59 Language Translator Programs Translate instructions written in programming languages into machine language Assembler Translates assembler language statement Compiler Translates high- level language statements Interpreter Translates and executes each statement in a program, one at a time

60. 4-60 Programming Tools Help programmers identify and minimize errors while they are programming –Graphical programming interfaces –Programming editors –Debuggers CASE Tools –A combination of many programming tools into a single application with a common interface –Used in different stages of the systems development process