1. CHAPTER 14. COMPUTER SOFTWARE

2. SOFTWARE
Detailed instructions to control computer operation. There are two major types of software:
System software: manages computer resources. Set of instructions that serves primarily as an intermediary between computer hardware and application programs. Manipulates computer hardware resources.
Application software: specific business application. A set of computer instructions that provide more specific functionality to a user. There are many different software applications in organizations today. Manipulate data or text to produce or provide information. *

3. Systems Software
Class of programs that control and support the computer system and its information-processing activities.
Systems software programs support application software by directing the basic functions of the computer.
For example, when the computer is turned on, the initialization program (a systems program) prepares all devices for processing.

4. Operating Systems Integrated system of programs that
Manages the operations of the CPU
Controls the input/output and storage resources and activities of the computer system
Provides various support services as the computer executes application programs

5. Operating Systems (continued)
Performs four basic functions
1: User interface: Provides a user interface
Allows humans to communicate with the computer
2: Resource management
Manages the hardware and networking resources of the system
Virtual memory capability

6. Operating Systems (continued)
3: File management
Controls the creation, deletion, and access of files of data and programs
Keeps track of the physical location of files
4:Task management
Manages the accomplishment of the computing tasks of end users
Multitasking
Multiprogramming
Timesharing

7. TRADITIONAL SINGLE-PROGRAM SYSTEM MULTIPROGRAMMING ENVIRONMENT
OPERATING SYSTEM
UNUSED MEMORY
PROGRAM 1
TRADITIONAL SINGLE-PROGRAM SYSTEM
OPERATING SYSTEM
UNUSED MEMORY
PROGRAM 1
PROGRAM 2
PROGRAM 3
MULTIPROGRAMMING ENVIRONMENT
The management of two or more tasks, programs, running on the computer system at the same time.

8. MULTITASKING MULTIPROGRAMMING ON A SINGLE-USER SYSTEM SUCH AS A
MICROCOMPUTER *

9. TIME SHARING It is an extension of multiprogramming.
In this mode, a number of users operate online with the same CPU, but each uses a different input/output terminal.
The programs of these users are placed into partitions in primary storage.
Execution of these programs rotates among all users, occurring so rapidly that it appears to each user as though he or she were the only using the computer.

10. Operating Systems (continued)
Popular Operating Systems
Windows
95, 98, ME NT
2000 XP
UNIX
Linux
Mac OS X

11. Types of Personal Application Software
WORD PROCESSING
SPREADSHEETS
DATA MANAGEMENT
GRAPHICS
DESKTOP PUBLISHING
GROUPWARE *

12. Types of Personal Application Software
Spreadsheets: Used for business analysis, planning, and modeling.
Computer spreadsheet software transforms a computer screen into a ledger sheet, or grid, of coded rows and columns.
They can be used for financial information, such as income statements or cash flow analysis.
They are also used for forecasting sales, analyzing insurance programs, summarizing income tax data, and analyzing investments.
They also offer data management and graphical capabilities. Ex: Ms Excel, Lotus

13. Types of Personal Application Software
Data management: Data management software supports the storage, retrieval, and manipulation of related data.
Produce forms, reports, & other documents.
Add, delete, update, and correct the data
Ex: Ms-Access.

14. Types of Personal Application Software
Word processing: allows the user to manipulate text rather than just numbers.
Many word processors contain many productive writing and editing features.
A typical word processing software package consists of an integrated set of programs including an editor program, a formatting program, a print program, a dictionary, a grammar checker, and integrated graphics, charting, and drawing programs.

15. Types of Personal Application Software
Desktop publishing: represents a level of sophisticated beyond regular word processing.
In the past, newsletters, announcements, advertising copy had to be laid out by hand and typeset.
Design and print newsletters, brochures, manuals, and books.

16. Types of Personal Application Software
Graphics: Graphics software allow user to create, store and display or print charts, graphs, maps and drawings.
It enables users to absorb more information more quickly and to spot relationships and trends in data more easily.
Ex: Ms-Power Point (Helps convert numeric data into graphic displays. Presentation graphics software)

17. Types of Personal Application Software
Groupware: it facilitates communication, coordination, and collaboration among people.
Helps workgroups and teams work together to accomplish group assignments.
Combines a variety of software features and functions
Discussion groups and databases
Scheduling
Task management
Audio and videoconferencing
Data sharing
Ex: Novell’s Group Wise, Oracle’s InterOffice.

18. Software Suits
Suites are a number of productivity packages bundled together
Microsoft Office
Lotus SmartSuite
Corel WordPerfect Office
Sun StarOffice

19. Software Suites (continued)
Advantages of suites
Cost
Similar graphical user interface
Share common tools
Programs are designed to work together
Disadvantages of suites
Large size
Many features never used by many end users

20. Web Browsers
Key software interface to the hyperlinked resources of the World Wide Web and the rest of the Internet. Easy-to-use software tools for displaying Web and the other Internet resources.
Internet Explorer
Netscape Communicator

21. Programming Languages
Programming languages allow people to tell computers what to do and are the means by which software systems are developed.

22. GENERATIONS OF PROGRAMMING LANGUAGES
1st. Since 1940s. MACHINE LANGUAGE: binary code
2nd. Since early ’50s. ASSEMBLER LANGUAGE: mnemonics for numeric code
3rd. Since mid ‘50s. HIGH-LEVEL LANGUAGES
4th. Since late ‘70s. FOURTH-GENERATION LANGUAGES *

23. Machine language Lowest-level computer language.
It is considered the first-generation language.
Composed of binary codes unique to each computer
Requires the programmer to write all program instructions in the 0s and 1s of binary code.
It is extremely difficult to understand, and use by programmers. Very slow.
As a result, increasingly more user-friendly languages have been developed.

24. Assembler language Next level up from machine language.
It is still considered a lower-level language but is more user-friendly.
Requires language translator programs called assemblers
Allows a computer to convert the instructions into machine instructions
Frequently called symbolic language

25. High-level languages Third generation
Uses instructions, called statements, that use brief statements or arithmetic expressions
Uses translator programs called compilers or interpreters
Syntax and semantics

26. HIGH-LEVEL LANGUAGES
FORTRAN (FORmula TRANslator): Scientific, Engineering applications
COBOL (COmmon Business Oriented Language): Predominant for transaction processing
BASIC (Beginners All-purpose Symbolic Instruction Code): General purpose PC language *

27. HIGH-LEVEL LANGUAGES
PASCAL: Used to teach structured programming practices. Weak in file handling, input / output
C: Powerful PC Language for developing applications. Efficient execution; cross platform. *

28. FOURTH GENERATION LANGUAGES (4GL)
Can be used by non-technical users to carry out specific functional tasks.
Called NONPROCEDURAL.
Can develop applications quickly
These languages greatly simplify and accelerate the programming process. *

29. FOURTH GENERATION LANGUAGES (4GL)
Examples of the 4GLs are query languages (SQL), report generators (RPG III), graphics languages (Visual C++) and PC software tools (WordPerfect, Ms-Access).

30. Object-oriented programming languages
Based on the idea of taking a small amount of data and the instructions about what to do with that data and putting both of them together into what is called an object.
Easier to use.
Creates reusable code.
Reduces time and cost of writing software.

31. OBJECT-ORIENTED PROGRAMMING
JAVA: Sun Microsystems OBJECT-ORIENTED PROGRAMMING LANGUAGE
Applet: tiny program to execute small function
Applets downloaded from network
Run on any computer & operating system
Designed for real-time, interactive, Web-based network applications *

32. OBJECT-ORIENTED PROGRAMMING
HTML (Hypertext Markup Language)
A page description language that creates hypertext or hypermedia documents
HTML is very easy to use.
The standard language the World Wide Web uses for creating and recognizing hypertext documents.