ComputerSoftware.pdf
- 2. GENERAL OBJECTIVES After studying this chapter, you should be able to: Define a computer software. Correctly classify software into system and application. Compare and contrast software into system and application. Understand the qualities of a good software Define an operating system. Understand the main computer user interfaces State and explain the types of Operating System. State and explain the functions of Operating System.
- 3. INTRODUCTION It is the collection of computer programs and related data that provide the instructions telling a computer what to do.
- 4. CATEGORIES OF SOFTWARE There are generally two broad types of software namely, systems software and application software. The relationship between them is shown in the diagram below. Application software System software Hardware
- 5. SYSTEM SOFTWARE System software controls and coordinates computer resources (hardware and software) so that the computer user and applications can smoothly interact. System software include: Operating Systems utility programs device drivers programming languages. BIOS (Basic Input/output System)
- 6. SYSTEM SOFTWARE CONT.. Operating System An operating system is a system software that manages the computer’s resources both hardware and software, and provides an interface through which a human can interact with the computer. Examples of OS include: Windows (XP, vista, 7, 8, 8.1, 10), UNIX, Linux, Mac OS X, MS-DOS.
- 7. SYSTEM SOFTWARE CONT.. OPERATING SYSTEM EXAMPLES
- 8. SYSTEM SOFTWARE CONT.. Utility Programs Utility software is software designed to help analyze, configure, optimize and maintain the computer. Examples of utility software include: disk defragmenters backup utilities disk compression utilities disk cleaners file managers anti-virus.
- 9. SYSTEM SOFTWARE CONT.. UTILITY PROGRAMS EXAMPLES
- 10. SYSTEM SOFTWARE CONT… EXAMPLES OF UTILITY SOFTWARE AND FUNCTION UTILITY SOFTWARE FUNCTION Disk defragmenters Detect computer files whose contents are broken across several locations on the hard disk, and move the fragments to one location to increase efficiency. Disk cleaners Find files that are unnecessary to computer operation, or take up considerable amounts of space. Disk cleaners help users decide what to delete when their hard disk is full. Backup utilities make copies of all information stored on a disk, and restore either the entire disk (e.g. in an event of disk failure) or selected files (e.g. in an event of accidental deletion).
- 11. SYSTEM SOFTWARE CONT.. EXAMPLES OF UTILITY SOFTWARE AND FUNCTION UTILITY SOFTWARE FUNCTION Disk compression utilities Reduce the space that a file takes up on disk, increasing the capacity of the disk. File managers Provide a convenient method of performing routine data management tasks, such as deleting, renaming, moving, copying, merging, generating and modifying data sets. Disk partition utilities Divide an individual drive into multiple logical drives, each with its own file system which can be mounted by the operating system and treated as an individual drive. Virus checkers Prevent, detect, and remove malware.
- 12. SYSTEM SOFTWARE CONT.. Programming Software Programming software usually provides tools to assist a programmer in writing computer programs, and software using different programming languages. These tools include: Compilers Interpreters Assembler Debuggers Linkers Loader
- 13. SYSTEM SOFTWARE CONT.. Programming Software ROLE Compilers Translate instructions written in a high-level language into machine language instructions. A compiler reads the whole source code at once before reporting errors. Interpreters Translates and executes instructions written in a high-level language into machine language instructions one line at a time. Assembler An assembler translates assembly language programs into machine code. Debuggers Detect and remove bugs. A bug is an error in a computer program Linkers Link parts of a computer program together. Loader Loader is a part of operating system and is responsible for loading executable files into memory and execute them.
- 14. SYSTEM SOFTWARE CONT.. BIOS (Basic Input/output System) BIOS or system BIOS is software stored on a non-volatile ROM chip built into the system on the motherboard. It is the first code that is run by the PC when powered on (boot firmware).
- 15. APPLICATION SOFTWARE Application software direct the computer to perform one or more specific tasks for the end user. They are designed to do the jobs that the user wants such as word processing, spreadsheets, database, and graphics.
- 16. APPLICATION SOFTWARE CONT… APPLICATION SOFTWARE EXAMPLES
- 17. APPLICATION SOFTWARE CONT… CATEGORIES OF APPLICATION SOFTWARE Application software include a variety of programs that can be divided into three categories: general-purpose applications special purpose applications tailor-made (bespoke) applications.
- 18. APPLICATION SOFTWARE CONT… GENERAL PURPOSE APPLICATION SOFTWARE General purpose application software or generic software is software designed to solve a wide range of related tasks. They are always available off-the-shelf ie. That is, they can be bought from the market.
- 19. APPLICATION SOFTWARE CONT… GENERAL PURPOSE APPLICATION SOFTWARE EXAMPLES GENERAL PURPOSE APPLICATION SOFTWARE TYPES OF PROCESSING EXAMPLES Database Software Organize and access large amounts of data. MS-Access, Oracle, Dbase, FileMaker Spreadsheet Software work with numbers, calcalations and graphs. MS Excel, Lotus 1-2-3, Quattro Pro, Apple Numbers Word Processing Software Create mainly text (Letters, term papers) MS Word, WordPerfect, WordPad, NotePad Presentation Software Build a slide presentation MS PowerPoint, HyperStudio, Digital Chisel Desktop Publishing Software generate layouts and produce quality text and images comparable to traditional printing MS Publisher, Adobe PageMaker, Quark Express Graphics Software Work with photos and arts. Corel Draw, Adobe Photoshop
- 20. APPLICATION SOFTWARE CONT… Special purpose Applications Special purpose applications are software designed or written for a particular situation or specific task. They are generally not available in shops unlike generic software and they often have to be purchased directly from the software manufacturer or a specialist firm. Special purpose Applications Examples Traffic control Payroll and time keeping Aircraft navigation Weather forecasting
- 21. APPLICATION SOFTWARE CONT… Bespoke (tailor-made) applications Bespoke application software is software written specifically for the needs of a user or company. It is "tailored" to their exact requirements.
- 22. ATTRIBUTES OF SOFTWARE Characteristics Descriptions Portability It is the ability for software to operate on multiple platforms. For example, will an application running in Windows run in GNU Linux. Reliability Reliability refers to the ability for software to perform its intended functions and operations in an environment without experiencing failure. Usability Usability is the measure of software’s potential to accomplish the goals of the user. Performance Performance tells us of how well the required features of software can perform assigned tasks. Availability Availability refers to the ratio of time software is functional to the total time it is required to function. Sometimes, it is expressed in qualitative terms, indicating the extent to which software can work. Efficiency Efficiency refers to how fast software will carry out a given task or a given set of tasks. It is often measured in time.
- 23. OPERATING SYSTEM An OS is a system software that manages the hardware and software resources of a computer, and serves as interface between the computer user and the computer.
- 24. COMPUTER USER INTERFACES OPERATING SYSTEM cont… Computer user interface also referred to as Human-Computer Interface (HCI), is the term used to describe the communication between humans and computer systems.
- 25. OPERATING SYSTEM cont… Command Line Interface is a user interface where the user types instructions through the a command prompt for the computer to carry out. E.g.MS-DOS and OS/2. Command Line Interface (CLI)
- 26. OPERATING SYSTEM cont… Graphical User Interface GUI is a user interface that uses computer graphics to ease the user’s operation. Commands are issued by using a pointing device to point and click on icons, buttons, menus and lists on the screen. Examples of GUI are MS Windows, Apple Macintosh and Linux OS.
- 27. OPERATING SYSTEM cont… Menu Driven Interface It is a user interface that allows the user to make use of features like menus, pointers or arrow keys to communicate with the computer. The user chooses an item from a displayed list. They are also called graphical character based user interface. Example, Mobile phones.
- 28. OPERATING SYSTEM cont… CLASSIFICATION OF OPERATING SYSTEMS Multiprogramming system Multi-tasking system Multi-user system Multi-processing system Multi-threading systems
- 29. OPERATING SYSTEM cont… TYPES OF OPERATING SYSTEMS Batch Processing Systems Real Time Operating Systems Network Operating Systems Embedded Operating Systems
- 30. OPERATING SYSTEM cont… Functions Of OS Resource Management Memory Management Processor Management: Task Management File management Providing a user interface
- 31. Review Questions 1. What is a computer software? 2. Explain what is meant by off-the-shelf. 3. State and explain the following qualities of a good software. 4. Define and give an example of an integrated software.