Operating system Basics for Computer Science.pptx
- 1. Lahore Garrison University 1 CSC351-Operating Systems Week-1 Lecture-1 Semester #05 Prepared by: Dr. M. Abubakar Qazi
- 2. Lahore Garrison University 2 Instructor Contact Details Name: Dr. Muhammad Abubakar Qazi Course Instructor: CSC351- Operating Systems Credit Hours: 3+1 Designation : Assistant Professor Email: abubakarqazi@lgu.edu.pk
- 3. 3 Course Learning Outcomes Upon completion of the course, students will be able to: Understand the characteristics of different structures of the Operating Systems and identify the core functions of the Operating Systems. 2. Analyze and evaluate the algorithms of the core functions of the Operating Systems and explain the major performance issues with regard to the core functions. 3. Demonstrate the knowledge in applying system software and tools available in modern operating systems.
- 4. 4 Recommended Resources Textbook Operating Systems Concepts, 9th edition by Abraham Silberschatz Other Modern Operating Systems, 4th edition by Andrew S. Tanenbaum Operating Systems, Internals and Design Principles, 9th edition by William Stallings Davis, W.S. and Rajkumar, T.M. (2004) Operating Systems: A Systematic View. 3rd Ed.Harlow, Addison- Wesley.
- 6. Agenda for Today Introduction and purpose of the course Organization of a computer system Purpose of a computer system—setting the stage for OS concepts and principles Outline of topics to be discussed in the course What is an operating system? History and Evolution
- 7. Structure of a Computer System A Computer System consists of: • Users (people who are using the computer) • Application Programs (Compilers, Databases, Games, Video player, Browsers, etc.) • System Programs (Shells, Editors, Compilers, etc.) • Operating System ( A special program which acts as an interface between user and hardware ) • Hardware ( CPU, Disks, Memory, etc.)
- 8. Layered View of a Computer System
- 9. Purpose of a Computer System Computer systems consist of software and hardware that are combined to provide a tool to solve specific problems in an efficient manner Execute programs
- 10. Computer System Hardware Keyboard Mouse Printer RAM/ROM HD Mem Bus System Bus Monitor CD Processor Floating Point Unit Integer Unit Cache Control Unit
- 11. Lahore Garrison University 11 What is an Operating System? A program that acts as an intermediary between a user of a computer and the computer hardware—provides the user a simpler (virtual) machine to work with A program that allocates and deallocates computer system resources in an efficient, fair, and secure manner—a resource manager system. It takes preventive measures whenever required to avoid errors. Why do we need an OS It manages the computer's memory and processes, as well as all of its software and hardware. It also allows you to communicate with the computer without knowing how to speak the computer's language. Without an operating system, a computer is useless.
- 12. Lahore Garrison University 12 Functions of Operating System It boots the computer It performs basic computer tasks e.g., managing the various peripheral devices e.g., mouse, keyboard It provides a user interface, e.g., command line, graphical user interface (GUI) It handles system resources such as computer's memory and sharing of the central processing unit(CPU) time by various applications or peripheral devices. It provides file management which refers to the way that the operating system manipulates, stores, retrieves and saves data. Error Handling is done by the operating system. It takes preventive measures whenever required to avoid errors.
- 13. Lahore Garrison University 13 Functions of Operating System
- 14. Operating System Goals Execute user programs and make solving user problems easier. Make the computer system convenient to use. Use the computer hardware in an efficient manner.
- 15. Lahore Garrison University 15 How OS Start and develop through ages The first operating systems were developed in the 1950s, when computers could only run one program at a time. Later in the following decades, computers began to include more and more software programs, sometimes called libraries, that came together to create the start of today's operating systems. In the late 1960s, the first version of the Unix operating system was developed. Written in programming language C Many modern operating systems, including Apple OS X and all different versions of Linux, date back or rely on the Unix OS. Microsoft Windows was developed in response to an IBM request for an operating system to run its range of personal computers or PCs.
- 16. Lahore Garrison University 16 How OS Start and develop through ages (Legacy OS to Modern OS) The first operating system created by Microsoft was not called Windows, it was called MS-DOS and it was built in 1981 when it bought the 86-DOS operating system from Seattle Computer Products and modified it to meet IBM requirements. The Windows name was first used in 1985 when a graphical user interface was created and paired or joined with the MS-DOS. Today, Apple, OS X, Microsoft Windows and the various forms of Linux (including Android) dominate the vast majority of the modern operating systems market,
- 17. Lahore Garrison University 17 MS-DOS Short for Microsoft Disk Operating System, MS-DOS is a non- graphical command line operating system derived from 86-DOS that was created for IBM compatible computers MS-DOS allows the user to navigate, open, and otherwise manipulate files on their computer from a command line instead of a GUI like Windows. Today, MS-DOS is no longer used; however, the command shell, more commonly known as the Windows command line is still used by many users. In MS-DOS, you would navigate to the folder using the cd command and then list the files in that folder using the dir command.
- 18. Lahore Garrison University 18 Windows The Windows operating system (Windows OS) for desktop PCs is more formally called Microsoft Windows and is actually a family of operating systems for personal computers. Windows provides a graphical user interface (GUI), virtual memory management, multitasking, and support for many peripheral devices. In addition to Windows operating systems for personal computers, Microsoft also offers operating systems for servers and mobile devices. Windows comes pre-loaded on most new PCs, which helps to make it the most popular operating system in the world.
- 19. Lahore Garrison University 19 UNIX/LINUX Unix is the most powerful and popular multi-user and multi-tasking Operating System.
- 20. Lahore Garrison University 20 OS2 The name stands for "Operating System/2", because it was introduced as part of the same generation change release as IBM's "Personal System/2 (PS/2)" line of second-generation personal computers. The first version of OS/2 was released in December 1987 and newer versions were released until December 2001. OS/2 has many of the same commands as DOS, can read DOS disks, but it is more sophisticated than DOS. In particular, OS/2 is a multi-tasking, multi-threaded operating system. S/2 also includes a graphical user interface, or GUI, called Presentation Manager, and which makes OS/2 look and work something like the Macintosh or Windows.
- 21. Lahore Garrison University 21 MAC Operating System The Macintosh Operating System (Mac OS) is an operating system (OS) designed by Apple Inc. to be installed and operated on the Apple Macintosh series of computers. Introduced in 1984, it is a graphical user interface (GUI) based OS that has since been released as multiple different versions. Mac OS is a completely capable OS that provides functionality and services like Windows or Linux OS. Some of the code base and features of Lisa OS have been incorporated in Mac OS. As of 2012, Mac OS released several versions, including Macintosh 128k, Mac OS 7, Mac OS X and Mac Mountain Lion.
- 22. Lahore Garrison University 22 Android Operating System Android is an open source and Linux-based Operating System The Android operating system is a mobile operating system that was developed by Google (GOOGL ) to be primarily used for touchscreen devices, cell phones, and tablets. Its design lets users manipulate the mobile devices intuitively, with finger movements that mirror common motions, such as pinching, swiping, and tapping. Google also employs Android software in televisions, cars, and wristwatches—each of which is fitted with a unique user interface. Android applications are usually developed in the Java language using the Android Software Development Kit. Once developed, Android applications can be packaged easily and sold out either through a store such as Google Play, SlideME, Opera Mobile Store, Mobango, F-droid and the Amazon Appstore.
- 23. Lahore Garrison University 23 iOS iOS is a mobile operating system developed by Apple. It was originally named the iPhone OS but was renamed to the iOS in June 2009. The iOS currently runs on the iPhone, iPod touch, and iPad. Like modern desktop operating systems, iOS uses a graphical user interface, or GUI. iOS, an acronym for iPhone Operating System, is a Unix-derived operating system powering all of Apple’s mobile devices The first version of iOS introduced the culture to the touch-screen smartphone, a significant cultural shift away from flip phones and Blackberry-style devices. The iPhone combined many functions within a single device, including a camera, internet browser, and media player alongside the phone and messaging, and the world would never be the same
- 24. Course Outline Operating system concepts Operating system structures Introduction to UNIX/Linux user interface Processes and threads—scheduling, concurrency, synchronization, etc. Deadlocks Memory management Virtual memory File system Secondary storage management
- 25. Introduction to UNIX/Linux Directory structure Browsing directory structure Useful commands
- 26. Processes Process concept (process, states, attributes, etc.) Process scheduling (scheduler) Context switching (dispatcher) Operations on processes (creation, termination, signaling, suspend, foreground, background, etc.) Process management in UNIX (fork, wait, exec, exit, etc.)
- 27. Processes (continued) Sample code for UNIX/Linux process management Cooperating processes Interprocess communication (IPC) IPC in UNIX/Linux (pipe, FIFO, socket, message queue, etc.) Communication between UNIX/Linux processes (pipe, mkfifo, read, write, close, etc.) Sample code UNIX/Linux processes (process images, control structures, etc. explained with sample code) Managing UNIX/Linux processes (ps, top, fg, bg, <Ctrl-Z>, <Ctrl-C>, etc.)
- 28. Threads Thread concept (thread, states, attributes, etc.) User- and kernel-level threads POSIX threads (the pthread library) Sample code
- 29. CPU Scheduling Basic concepts Scheduling criteria Scheduling triggers Scheduling algorithms UNIX System V scheduling algorithm Optimal scheduling Algorithm evaluation
- 30. Process Synchronization Basic concept The Critical Section Problem Solutions for the Critical Section Problem Software-based solutions—the Bakery Algorithm Hardware-based solutions Semaphores Binary and counting semaphores
- 31. Process Synchronization … Classic problems of synchronization Deadlocks and starvation Critical regions Monitors Synchronization tools used in Solaris, Linux, and Windows Deadlocks and starvation Pthread library functions
- 32. Deadlocks Basic concept Deadlock characterization Deadlock handling (prevention, avoidance, detection and recovery) Banker’s algorithm
- 33. Memory Management Basic concepts Various techniques for memory management Logical to physical address translation Swapping Contiguous memory allocation: MFT, MVT External fragmentation Paging Hardware support for paging Internal fragmentation
- 34. Memory Management … Performance of paging Protection and sharing Page table issues: Multi-level paging, Hashed page tables, Inverted page tables Segmentation Protection and sharing Segmentation with paging Intel P4 example
- 35. Virtual Memory Basic concept Demand paging Page fault Performance of demand paging Page replacement Allocation of frames Thrashing Operating-system examples Other considerations (I/O locking, page size, …)
- 36. File System Interface Basic concepts (file attributes, operations, types, structure, etc.) Access methods (sequential, random, etc.) Directory structure UNIX/Linux directory structure (links in UNIX) File system mounting, sharing, and protection UNIX/Linux examples for sharing and protection, and relevant commands (chmod, ln, ln –s, etc.)
- 37. File System Implementation Basic concepts (overview of disk structure, file structure, boot control block, super block, per process file descriptor table, system-wide open-file table, etc.) Directory implementation Free space management methods Space Allocation Methods Time and space performance of allocation methods Brief introduction to Network File System (NFS)
- 38. Mass Storage Structure and Scheduling Disk structure and scheduling Disk management (formatting, boot block, bad blocks, etc.) Course Recap
- 39. 39 Summary Today we learnt about Operating System Basics Course Outline