1. An operating system acts as an intermediary between hardware and software applications, managing computer resources like the CPU and peripheral devices while providing a user interface and executing services for other programs. 2. Common personal computer operating systems include Windows and Mac OS, with Windows being the most popular. Windows XP brought consumer and corporate versions together and improved the user interface, personalization, and security features. 3. Network operating systems handle network functions like sharing resources between computers on a network, providing data security and administrative control over the network.

1. Computers: Tools for an Information Age Chapter 3 Operating Systems: Software in the Background

2. Objectives Describe the functions of an operating system Explain the basics of a personal computer operating system Describe the advantages of a graphical operating system Differentiate among different versions of Microsoft Windows Explain the need for network operating systems Describe the methods of resource allocation on large computers Describe the differences among multiprocessing, multiprogramming, and time-sharing Explain the principles of memory management List several functions that are typically performed by utility programs

3. Operating Systems: Hidden Software Serves as intermediary between hardware and applications software Operating System Systems software Kernel

4. Operating System A set of programs that lies between applications software and the hardware Manages computer’s resources (CPU, peripheral devices) Establishes a user interface Determines how user interacts with operating system Provides and executes services for applications software

5. Systems Software All programs related to coordinating computer operations Examples Operating systems Language translators Convert program code to machine-readable form Utility programs Perform secondary chores

6. Kernel Manages the operating system Loaded from hard drive into memory when computer is booted Booting refers to starting the computer Loads other operating system programs from disk storage as needed Other programs referred to as nonresident

7. Operating Systems for Personal Computers Platform: combination of computer hardware and operating system software Wintel (Microsoft Windows running on an Intel-based PC) is one of the most common Common Platforms MS-DOS Windows MAC OS Unix Linux Your Assignment: Comparison Matrix

8. Graphical User Interface User clicks an icon to perform tasks Start Menu in lower left corner launches programs Use menus to activate commands

9. Windows XP Brings consumer and corporate versions of Windows together into a single product Has Home and Professional Editions

10. Windows XP Enhancements Improved user interface Much clearer and uncluttered desktop More icons on redesigned Start Menu Improved multimedia support More personalization Multiple user support User can log off, leaving programs running, and allow another user to log on Set up limited accounts for children to use; i.e., no inappropriate games or no Internet access Internet support and protection

11. Operating Systems for Networks Network operating system (NOS) Handles network functions Sharing resources (hard disks and printers) Data security Troubleshooting Administrative control Make resources appear as though they were running from client computers

12. Operating Systems for Large Computers Resource allocation: assigning computer resources to certain programs and processes for their use Main issues related to resource allocation Sharing the Central Processing Unit Multiprocessing Multiprogramming Time-Sharing Sharing memory Sharing storage resources Sharing printing resources

13. Sharing the CPU Multiprocessing The use of a powerful computer with multiple CPUs Multiple programs run simultaneously (each runs on its own processor) Multiprogramming Two or more programs executed concurrently Programs take turns using the CPU Event-driven Time-Sharing Programs take turns using the CPU Time-driven Typically used in applications with many users

14. Sharing Memory Memory management Divides memory into foreground and background Uses virtual storage (also called virtual memory) Programs currently executed are stored on disk Portions of program brought into memory as needed Minimizes the amount of memory needed Can be implemented by paging Divide memory into small, fixed-size pages Page table keeps track of memory locations

15. Sharing Storage Resources Keeps track of location of files Responds to commands to manipulate files Keeps track of input and output requests for files Processes them in the order received

16. Sharing Printing Resources Spooling: program writes a line to a disk file rather than sending directly to a printer When file is completed, placed in queue File printed when printer becomes available Allows program to complete execution much more quickly Writing to disk much quicker than writing to printer

17. Utility Programs Perform secondary chores – some examples: File manager Stores files in a hierarchical directory structure Windows uses Windows Explorer File compression Reduces amount of space a file requires Makes file take up less space on disk Takes less time to transmit across communication lines Others Backup and Restore Backup: make copies of disks and store in a safe place Restore: restore files from backups Disk defragmenter: reorganizes disk so all files are stored in contiguous locations Device driver: handles commands for devices, such as printers and storage devices

18. Systems Software Questions? Types of System Software? Functions? Utility Programs? Operating Systems?

19. Graphical user interface (GUI) Kernel Memory management Multiprocessing Multiprogramming Operating system Partitions Platform Terms to Know: Chapter 3 Resource Allocation Response time Spooling Time share Utility programs Virtual Memory/Storage

20. Can You Explain If Asked? Describe the functions of an operating system Explain the basics of a personal computer operating system Describe the advantages of a graphical operating system Differentiate among different versions of Microsoft Windows Explain the need for network operating systems Describe the methods of resource allocation on large computers Describe the differences among multiprocessing, multiprogramming, and time-sharing Explain the principles of memory management List several functions that are typically performed by utility programs

21. Sources Capron; Computers: Tools for An Information Age, 8 th Ed. 2003 Pfaffenberger; Computers in Your Future 2003 Microsoft Clipart Webopedia