1. 1GMS-VU : Module 2 Introduction to Information and Communication Technologies Module 2 Computer Software

2. 2 Scope n What is software? n What are the types of software? n How is software created? n What are some problems in using software? n How do you ensure security of the system and data? n What are future trends in software development?

3. 3 Learning Outcomes By the end of this lesson, you should be able to: 1. Define the functions of software in a computer system 2. Identify the different types of software 3. List different types of operating systems and application software 4. Identify steps in creating software 5. Identify problems in using software 6. Describe the ways to ensure security of the system and data 7. Identify general trends in software development

4. 4GMS-VU : Module 2 What is software? n A computer system is generally composed of hardware and software. n Hardware makes up the physical components. n Software makes up the set of instructions for the computer. Without software, the computer will not be able to perform the tasks required. n Sometimes software is called a computer program.

5. 5 What are the types of software? There are two sets of instructions that a computer must follow: n System software such as DOS, Windows, Linux, Unix, and Mac OS System software n Application software such as those used for word processing, spreadsheets, or library management Application software

6. 6 System Software n An organized collection of system programs which serve as the interface between the computer hardware and the user application n It manages the hardware resources: u Operating System F CPU management to facilitate sharing execution time of processes F Memory management to allocate memory resources dynamically F I/O management to handle reading and writing devices u Compiler/Interpreter u Utilities CPU Memory I/O

7. 7 Examples of Operating Systems  Disk Operating System (DOS)  Microsoft Windows  Mac OS  LINUX  UNIX  Other Proprietary OS

8. 8 n A generic term describing any operating system that is loaded from disk devices n It is not a user friendly OS since users need to memorize commands and issue them by typing line by line, known as command line interface. n Very few end users use DOS nowadays. Disk Operating Systems (DOS)

9. 9 Microsoft Windows n A Graphical User Interface (GUI), which was originally run on DOS (Windows 3.x), that allows multitasking or the ability to run several programs at the same time n Examples: u Microsoft Windows 95 u Microsoft Windows 98 u Microsoft Windows 2000 u Microsoft Windows XP

10. 10 Application Software n A set of instructions designed to perform a specific task such as word processing, accounting, cataloguing, library management, animation, etc. n The type of the software depends on the application F General purpose office software F Business software F Special purpose and other software

11. 11 General Purpose Office Software n Word processing: e.g. MS Word n Spreadsheets: e.g. MS Excel n Database management systems: e.g. MS Access, SQL n Presentation/Graphics: e.g. MS PowerPoint, Adobe Photoshop n Software suite: e.g. MS Office *MS stands for Microsoft

12. 12 Business Software A set of software used for business application such as software for banking, e-Commerce, etc.

13. 13 Special purpose software and other software n Desktop publishing software: e.g. MS Publisher n Imaging and drawing: e.g. Corel Draw n File management: e.g. CDS/ISIS, INMAGIC n Library management software: e.g. Athena, VTLS, INNOPAC, Library Solutions n Other Software: e.g. Statistics and registration software, etc.

14. 14 How is software created? Software Development Process 2.0 Software Design 1.0 Software Analysis 3.0 Programming/ Coding 4.0 Compiling 5.0 Testing and Debugging 6.0 Implementing and maintenance

15. 15 1.0 Software Analysis To identify problems and user requirements 2.0 Software Design To illustrate what the software will do and what output will be generated

16. 16 3.0 Programming/Coding To create the software by translating specifications and requirements into program instructions 4.0 Compiling To translate program instructions into machine language

17. 17 5.0 Testing and Debugging To examine whether the software is error free and produces the intended results 6.0 Implementing and Maintenance To install and operate the software efficiently

18. 18 Programming Languages Programming languages are used to write software. Some of these are: u Low level languages F Assembly u High level languages F COBOL F FORTRAN F C++ F Pascal F Visual Basic u Programming languages for the Internet F Perl F Java F HTML F XML

19. 19 What are problems in using software? n Programming languages n Character sets n Malicious Software

20. 20 Problems caused by programming languages n Programming languages are usually in English. n Applications usually use the English language and the Roman alphabet. n Problems arise when the user is non-English and/or is using non-Roman script.

21. 21 Problems caused by different characters sets n Computers use character sets stored in binary codes. n Different scripts use different character sets. n Computers must know which writing system/character set they are dealing with.

22. 22 Problems caused by malicious software  Computer VirusComputer Virus  WormWorm  Trojan HorseTrojan Horse

23. 23 n A program or a code that gains access without the users ’ knowledge and/or perform actions not intended by the user, often damaging data and sometimes the whole system in the process. n Viruses are activated once unknowing users run, open, view or copy the file containing it. n The action that will trigger the virus to deliver its “ payload ” depends on the type of virus that infected the file. Computer Virus

24. 24 Characteristics of a virus n A self-replicating program whose main purpose is to propagate itself to as many places as possible n Self-propagating by modifying another program to include itself by an act of a user, e.g. opening/ viewing files unknowing that they are infected and/or copying/transferring files from one system to another through diskettes, file transfer, e-mail, the internet and other means …

25. 25 Worm n A program that replicates and propagates itself without any action from the user n This differentiates it from a virus that needs user action in order to replicate.

26. 26 n A Trojan horse contains hidden functions that, while running, may destroy files or create a “ back door ” allowing an intruder to access the system. n A Trojan horse, unlike a virus, does not spread by itself but can be as destructive, depending on the intentions of the intruder. Trojan Horse

27. 27 How do you ensure security of the system and data? n Back-up your system and your data regularly by using CD-R, CD-RW, diskettes, tapes, or another hard disk. n Use firewalls, encryption and other security measures to protect data, computer systems and networks from intrusion and attacks done through the Internet. n Protect yourself from malicious software: Virus/Worm/Trojan Horse.

28. 28 Protect yourself from viruses, worms and Trojan horses n Refrain from running any program or opening any file from untrusted sources. n Scan floppy diskettes and CD-ROMs before using. n Install a virus shield to automatically check diskettes and CDs. n Get an updated version of a virus scan program. n Always check you hard disk for possible infection, if you are connected to the Internet. n Use diskettes only after they have been scanned.

29. 29 What are future trends in software development? n More user friendly n More customized n More Web enabled n More flexible/compatible n More sophisticated u programming languages u functions