Introduction to Operating system
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This document discusses several topics related to operating systems and computer science. It begins by discussing storage media such as CDs, DVDs, tapes, and solid state storage. It then poses questions about why operating systems should be studied and some benefits of doing so. Specifically, it notes that operating systems are large, complex software that manages hardware resources and concurrency. The document also discusses why operating systems will not go away due to their fundamental role in making hardware useful. It provides an overview of the capstone operating systems course and focuses on design and implementation challenges. Finally, it covers some administrative details of the course.
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Introduction to Operating system
- 1. 1 Issues and Non-issues in the press Storage in crisis Will CD’s be readable in 50 years? Will VHS tapes be readable in 20? Will anyone care? Backup Media 2 TB Disk $231, available now. (1.5TB $129) DVD is 4.3 GB, dual layer 8 GB, Blu-ray 50 GB Current backup tapes 100-800 GB 1 in 10 recover attempts fail (?) – Gartner Group Solid state storage No moving parts, lower energy consumption, better random read performance. 128GB is $307 in 2009 (256GB is $609)
- 2. 2 Aren’t Operating Systems Dead? The operating system (OS) I use has already been written, and I doubt it will be my job to write another one. For example, Windows, Linux. … So, why should I study operating systems? Haven’t OS developers figured everything out already? What more is there to do? Why should I study this as an undergraduate? Studying OS design IS studying design of large software systems. OS is needed to make hardware useful. Please think of one question you have about computing
- 3. 3 Why Study Operating Systems? Because OS hacking will make you a better programmer and a better thinker. The OS is really large (Windows Vista is 50 million lines+). The OS manages concurrency. Concurrency leads to interesting programming challenges. (Interesting programming challenges can lead to wisdom.) OS code manages raw hardware. Programming raw hardware is challenging: timing dependent behavior, undocumented behavior, HW bugs. OS code must be efficient, low CPU, memory, disk use. OS fails ⇒ machine fails. OS must fail less than user programs. OS provides services that enable application programs … knowledge of OS will make you a better computer user OS basis of system security.
- 4. 4 Why Won’t Operating Systems Go Away? Hardware needs an OS to be useful. Multiplex resources for efficiency and security. OS is cornerstone of what makes computing fun. The design of an MP3 player involves many OS issues: Its OS implements a file system which is specially designed to store music files. The OS manages communication with your PC. The OS reads music from the disc and buffers it in memory. The OS controls the volume of the output device. The OS controls the display. The OS controls wireless network access. Cell phone, mp3 player, DVD player, TIVO, PDA, iPhone, eBook reader, peer-to-peer file sharing Systems/Theory/Artificial intelligence
- 5. 5 Issues repeat Controlled hardware Uncontrolled hardware Macintosh Windows Peripherals are expensive, e.g., memory, disks Open market drives down prices Stable platform Device drivers breed instability iPhone Android Apple has tightly controlled the introduction of new iPhones and updates to its operating system. Three versions of the OS (Android 1.5, 1.6 and 2.0), custom firmware on many phones, and hardware differences between different models. It has just three iPhone models since 2007. All iPhone users are prompted to update their phones to be on the same version of the OS. You may build an app that works perfectly with all three firmwares, but then when you run it on carriers’ ROMs it completely blows up Is it a computing platform or an appliance?
- 6. 6 CS372 Capstone course Combines skills from many different courses Programming languages Data structures Algorithms Projects Build components of an operating system Thread/process manager, memory management, file system, … Enhance software engineering skills Thread programming, build large systems, group projects Practical computer science is heavy on learn by doing The engineering in computer science
- 7. 7 Design and Implementation Design problems. Understand the problem, and define it. Understand the space of possible solutions, previous approaches Formulate your own approach and justify why it might work. Implementation issues. Real systems are more difficult to build than to explain. The devil is often in the details. Building a system gives you satisfaction, and feeling of accomplishment. Mix of specific and general One way to do memory management (but a very interesting way). Many scheduling algorithms. Light on details of specific OSes, look at larger issues that change infrequently
- 8. 8 Administrivia iClicker We will use the iClicker system. Almost exclusively for in-class use to make sure y’all are following the material It beats relying on the 5 students who like to talk It avoids pressuring individuals
- 9. 9 Administrivia Collaboration and Cheating Working in groups on homeworks is OK but… You can only collaborate with other students in the course Every student must craft their own final solution Every student must fully write up their solution All collaborators must be acknowledged in writing Collaboration Discuss problem sets and programming assignments Discuss possible interpretation of questions, technical details Cheating Copying solutions code or programs from someone else, previous year’s solutions, or public domain Providing material for someone else to imitate IS still cheating. Participate in discussion group where one person writes solution and everyone else copies it Grading 5 lab slip days Pair programming Your visa status. Your parents coming to graduation, etc.
- 10. 10 Administrivia Attendance & Classroom Ettiquette Attendance is expected Important things will be announced in class Slide questions will be answered in class I take attendance with iclicker If you will miss many classses, you can email me with your reasons No laptops in class I don’t mind your watching youtube, but it distracts others Lecture notes Lecture notes are provided for your convenience Exam review notes are provided for your convenience What is said in class takes precedence You must read the book or external sources Class/notes is for high-level concepts Lab & reading is for low-level details Labs and exams rely on low-level details Book is optional, but reading is NOT
- 11. 11 Administrivia Where to go for help? Attend class. Unannounced in-class quizzes to encourage attendance. Ask questions in class. Exercise your understanding of the course material on a daily basis Attend office hours Emmett’s office hours are W 14:30-15:30 in ACES 6.240 Naga’s office hrs: T 2:30-3:30pm, F 11am-12, Taylor basement If you can’t come to office hours, set up an appointment Please limit e-mail to personal issues. Use the blackboard discussion board
- 12. 12 Course Overview OS Structure, Processes and Process Management CPU scheduling Threads and concurrent programming Thread coordination, mutual exclusion, monitors Deadlock Virtual memory & Memory management Disks & file systems Distributed file systems Security Review of the movie, Primer.
- 13. 13 Administrivia Course Information and Handouts Slides are available online. A course packet is available. Updates will be made during the semester. http://www.cs.utexas.edu/~witchel/372