© 2009 Prentice-Hall, Inc. 1 Chapter 4 Using System Software: The Operating System, Utility Programs, and File Management Computer Skills For Preparatory Programs "Applied1 Track" CS 051

After reading this chapter, you should be able to answer the following questions: 1. 1.What software is included in system software? 2. 2.What are the different kinds of operating systems? 3. 3.What are the most common operating systems? 4. 4.How does the operating system provide a means for users to interact with the computer? 5. 5.How does the operating system help manage resources such as the processor, memory, storage, hardware, and peripheral devices? 6. 6.How does the operating system interact with application software? 7. 7.How does the operating system help the computer start up? 8. 8.What are the main desktop and window features? 9. 9.How does the operating system help me keep my computer organized? What utility programs are included in system software, and what do they do? © 2009 Prentice-Hall, Inc. 2 Chapter Objectives

© 2009 Prentice-Hall, Inc. 3 Chapter Topics System softwareSystem software Kinds of operating systemsKinds of operating systems OS role in:OS role in: –Providing user interaction –Managing the processor –Managing memory –Managing hardware –Interacting with application software –Starting the computer

© 2009 Prentice-Hall, Inc. 4 Chapter Topics (cont.) Desktop and windows featuresDesktop and windows features OS role in keeping desktop organizedOS role in keeping desktop organized Utility programsUtility programs

System software consists of two primary types of programs:consists of two primary types of programs: –Operating system (OS): the main program that controls how your computer system functionsthe main program that controls how your computer system functions –Utility programs: Is a small program that performs general house- keeping tasks for the computerIs a small program that performs general house- keeping tasks for the computer © 2009 Prentice-Hall, Inc. 5

6 System Software: The OS 1.Controls computer functions 2. The OS manages the Computer’s: HardwareHardware ProcessorProcessor MemoryMemory DevicesDevices 3. Provides means for software to work with the CPU 4. Responsible for management, scheduling, and interaction of tasks 5. Provides user interface

© 2009 Prentice-Hall, Inc. 7 What the OS Does? 1.Provides user interface 2.Manages the CPU 3.Manages memory and storage 4.Manages hardware and peripheral devices 5.Coordinates application software with the CPU

© 2009 Prentice-Hall, Inc. 8 System Software: Utilities Utilities:Utilities: Programs that perform computer housekeeping tasks Programs that perform computer housekeeping tasks –Manage system resources –system maintenance –file compression. –Improve efficiency –Virus prevention

© 2009 Prentice-Hall, Inc. 9 Operating System Categories Operating systems are classified into four categories, depending on:Operating systems are classified into four categories, depending on: 1. the number of users they serve 2. the tasks they perform. Categories:Categories: 1. 1.Real-Time (RTOS) 2. 2.Single-User, Single-Task OS 3. 3.Single-User, Multitask OS 4. 4.Multiuser OS

© 2009 Prentice-Hall, Inc. 10 Real-Time Operating Systems (RTOS) Systems with a specific purpose and a certain result.Systems with a specific purpose and a certain result. Real-time operating systems don’t require the intervention of any users at all.Real-time operating systems don’t require the intervention of any users at all. Uses include:Uses include: –Industrial machines –Robotic equipment –Automobiles –Video game consoles –Home appliances

© 2009 Prentice-Hall, Inc. 11 Single-User Operating Systems Single-task systems –Perform one task at a time Examples: 1.PDAs: they require single-user, single- task operating system software such as:they require single-user, single- task operating system software such as: Palm OS Palm OS Windows MobileWindows Mobile 2. Microsoft Disk Operating System (MS-DOS) Multitask systems Perform simultaneous tasks Windows MAC OS Linux

© 2009 Prentice-Hall, Inc. 12 Multiuser Operating Systems Known as network operating systemsKnown as network operating systems Allow access to the computer system by more than one userAllow access to the computer system by more than one user Manage user requests.Manage user requests. Systems include: –Linux –UNIX –Novell Netware –Windows Server 2003 –Windows XP –Windows Vista

© 2009 Prentice-Hall, Inc. 13 Desktop and Notebook Operating Systems PlatformPlatform Operating system combined with the processor. Operating system combined with the processor. –Microsoft Windows/Intel –Apple Macintosh/Motorola

© 2009 Prentice-Hall, Inc. 14 Desktop and Notebook Operating Systems (Conti.) Desktop and notebook operating systems include:Desktop and notebook operating systems include: –Microsoft Windows –MAC OS –Linux –UNIX

Windows Microsoft Windows began with MS-DOS.Microsoft Windows began with MS-DOS. In 1995, they incorporated a user-friendly Interface and Multi-tasking capabilities that was released as Windows 95.In 1995, they incorporated a user-friendly Interface and Multi-tasking capabilities that was released as Windows 95. Windows XPWindows XP was a major update that provided Networking capabilities.was a major update that provided Networking capabilities. Windows 7Windows 7 is the newest release featuring Security and user- interface upgrades. is the newest release featuring Security and user- interface upgrades. Windows improvements have concentrated on:Windows improvements have concentrated on: – increasing user functionality and friendliness –Improving internet capabilities and enhancing file privacy and security. © 2009 Prentice-Hall, Inc. 15

© 2009 Prentice-Hall, Inc. 16 MAC OS First commercially available OS with point-and-click technology (graphical user interface) Mac OS X, is based on the UNIX operating system. Excellent in: – –Graphics display – –Processing capabilities – –System reliability – –Document recovery Fewer software applications available

© 2009 Prentice-Hall, Inc. 17 Linux Open-source operating systemOpen-source operating system Based on UNIXBased on UNIX Stable systemStable system Free to developersFree to developers May be downloaded through the InternetMay be downloaded through the Internet

© 2009 Prentice-Hall, Inc. 18 Operating Systems for Servers and Mainframes Servers – –Computers on a network that manage network resources, Mainframes – –Handle requests from hundreds or thousands of users simultaneously Operating Systems: – –Windows Server – –Unix

© 2009 Prentice-Hall, Inc. 19 UNIX Multiuser, multitask operating systemMultiuser, multitask operating system Used primarily with mainframesUsed primarily with mainframes

© 2009 Prentice-Hall, Inc. 20 The User Interface Enables you to interact with the computer Types of interfaces: 1. 1.Command-driven interface: -The user had to type very specific commands to get the computer to load a program.

The User Interface (Conti.) 2. Menu-driven interface: by incorporating a menu-driven interface in which you choose a command from menus displayed on the screen. Eliminated the need to know every command because you could select most of the commonly used commands from a menu. 3. Graphical user interface (GUI): GUIs display graphics and use the point-and- click technology of the mouse and cursor, making them much more user friendly. © 2009 Prentice-Hall, Inc. 21

© 2009 Prentice-Hall, Inc. 22 Processor Management Controls the timing of events the processor works on. – –Interrupts: Is a signal that tells the OS it is in need of attention to perform a task – –Interrupt handler: special numerical code that prioritizes the requests – –Preemptive multitasking: The OS processes the task assigned a higher priority before processing A task that has been assigned a lower priority.

Processor Management (Conti.) – –Interrupt table: A special place in RAM that the requests are placed in. – –Stack : Is a special location in RAM that the CPU puts a “memo” so it can know where he was before the interrupt. © 2009 Prentice-Hall, Inc. 23

© 2009 Prentice-Hall, Inc. 24 Memory and Storage Management The operating system allocates space in RAM for instructions and data.The operating system allocates space in RAM for instructions and data. RAM Operating System OS gets ready data to process OS ensure there are free space to allocate data OS clears items from RAM when the processor no longer needs

Virtual Memory Virtual Memory : – –The process of optimizing RAM storage by borrowing hard drive space. – –Swap File: When more RAM space is needed, the OS moves from RAM the data or instructions that have not been recently used to a temporary storage area on the hard drive. – –Paging : If the data and/or instructions in the swap file are needed later, the OS swaps them back into RAM. – –Thrashing: The condition of excessive paging. © 2009 Prentice-Hall, Inc. 25

© 2009 Prentice-Hall, Inc. 26 Virtual Memory Instructions and data are stored on the hard drive when RAM is full.Instructions and data are stored on the hard drive when RAM is full. Operating System RAMHard Disk Data & instruction not recently Used Data & instruction needed now

© 2009 Prentice-Hall, Inc. 27 Hardware and Peripheral Device Management Device drivers –Programs that enable the operating system to communicate with peripheral devices –Provided by the manufacturer of the device Plug and Play (PnP) –Driver preinstalled in Windows –PnP is Hardware and software standard –PnP facilitates the installation of new hardware (immediately use the device, when it plugged to the port)

© 2009 Prentice-Hall, Inc. 28 Software Application Coordination Application programming interfaces (APIs)Application programming interfaces (APIs) –Blocks of code contained in the operating system, so that the software programs can work with the CPU. –API code must recognize by CPU. –Coordinates the operating system (OS) with software applications Similar toolbars and menusSimilar toolbars and menus

Software Application Coordination (Conti.) Software programmers need only refer to the API code blocks in their individual application programs rather than including the entire code in the application itself.Software programmers need only refer to the API code blocks in their individual application programs rather than including the entire code in the application itself. –APIs avoid redundancies in software code. –Make it easier for software developers to respond to changes in the OS. © 2009 Prentice-Hall, Inc. 29

Software Application Coordination (Conti.) An example of API:An example of API: –Microsoft DirectX: is a group of multimedia APIs built into the Windows operating system is a group of multimedia APIs built into the Windows operating system Improves graphics and sounds when you’re playing games or watching video on your PC.Improves graphics and sounds when you’re playing games or watching video on your PC. © 2009 Prentice-Hall, Inc. 30

© 2009 Prentice-Hall, Inc. 31 Starting the Computer The Boot Process Step 1: The basic input/output system (BIOS) is activatedStep 1: The basic input/output system (BIOS) is activated Step 2: A power-on self-test (POST) checks attached hardwareStep 2: A power-on self-test (POST) checks attached hardware Step 3: The operating system loads into RAMStep 3: The operating system loads into RAM Step 4: Configuration and customization settings are checkedStep 4: Configuration and customization settings are checked

© 2009 Prentice-Hall, Inc. 32 Handling Errors in the Boot Process Safe modeSafe mode –Windows does not boot properly –Try rebooting –Uninstall any new devices or software

© 2009 Prentice-Hall, Inc. 33 Chapter 4 Summary What software is included in system software? What are the different kinds of operating systems?What are the different kinds of operating systems? What are the most common desktop operating systems?What are the most common desktop operating systems? How does the operating system provide a means for users to interact with the computer? How does the operating system help manage: – –the processor? – –memory and storage? – –hardware and peripheral devices? How does the operating system interact with application software?

© 2009 Prentice-Hall, Inc. 34 How does the operating system help the computer start up? What are the main desktop and windows features? How does the operating system help me keep my computer organized? What utility programs are included in system software, and what do they do? Chapter 4 Summary

© 2009 Prentice-Hall, Inc. 35 The End Next : Chapter The Internet and World Wide Web