CSMC 412Operating SystemsProf. Ashok K Agrawala© 2006 Ashok AgrawalaAugust 06 1CMSC412 Set 1Dayalbagh Eductional InstituteWelcomeToday• Review Syllabus– read the warning about the size of the project– Preferred 7thedition of the book. If you have 6th.• Program #0 Handout (posted on the web)– its due in just over one week– purpose is to get familiar with the simulator/compiler/debugger• Class Grades Server– Grades.cs.umd.edu• Discussion Sections– will focus on the project and meet only once a week • Probably will have two times per week; you can attend the section of your choice. See web page for details.• Reading– Chapter 1 – Chapter 2August 06 3CMSC412 Set 1Class Grades Serverhttp://grades.cs.umd.edu• Get your LinuxLab account from here– CS computing cluster. Projects must work and be submitted on these machines• Complete grade information• Interface for requesting regrades on exams and projectsAugust 06 4CMSC412 Set 1Catalog Description• A hands-on introduction to operating systems, including topics in: multiprogramming, communication and synchronization, memory management, IO subsystems, and resource scheduling polices. The laboratory component consists of constructing a small kernel, including functions for device IO, multi-tasking, and memory management.August 06 5CMSC412 Set 1Prerequisites• CMSC 311• CMSC 330August 06 6CMSC412 Set 1Topics Covered• - Introduction to Operating Systems (1 week)• - Concurrent Processes (2 weeks) • - Kernel implementation techniques (1 week) • - CPU scheduling (1 week) • - Memory Management (2 weeks) • - File and I/O Systems (2 weeks) • - Security and Protection (1 week)• - Networking and Distributed Systems (2 weeks)• - Objects and Naming (1 week)• - Window and Display Services (0.5 weeks)August 06 7CMSC412 Set 1Text• Required– Operating System Concepts 7th Edition, Siberschatz, Galvin and Gagne, John Wiley 2005.August 06 8CMSC412 Set 1Programming Projects:• Understanding operating system concepts is a hands-on activity. This class will include several substantial programming projects that will require students to read and understand provided code, write new modules, and debug the resulting system. The programming assignments will be time consuming and students taking this class should plan their class schedules accordingly.• The instructor reserves the right to fail, regardless of overall numeric score, students who do not submit a good faith attempt to complete all programming assignments.August 06 9CMSC412 Set 1Grading• Final Exam 30%• Midterms (2 each worth 15%) 30%• Programming Assignments 40%•• Exams: • Midterm #1 -• Midterm #2 -• Final August 06 10CMSC412 Set 1Introduction• What Operating Systems Do• Computer-System Organization• Computer-System Architecture• Operating-System Structure• Operating-System Operations• Process Management• Memory Management• Storage Management• Protection and Security• Distributed Systems• Special-Purpose Systems• Computing EnvironmentsAugust 06 11CMSC412 Set 1Objectives• To provide a grand tour of the major operating systems components• To provide coverage of basic computer system organizationAugust 06 12CMSC412 Set 1What Operating Systems Do• Computer system can be divided into four components– Hardware• CPU, memory, I/O devices– Operating system• Controls and coordinates use of hardware among various applications and users– Application programs• Word processors, compilers, web browsers– UsersAugust 06 13CMSC412 Set 1Computer System Structure• Computer system can be divided into four components– Hardware – provides basic computing resources• CPU, memory, I/O devices– Operating system• Controls and coordinates use of hardware among various applications and users– Application programs – define the ways in which the system resources are used to solve the computing problems of the users• Word processors, compilers, web browsers, database systems, video games– Users• People, machines, other computersFour Components of a Computer SystemAugust 06 15CMSC412 Set 1User View of a Computer• Varies according to the interface being used• Most systems designed for one user monopolizing its resources– OS maximizes the work (or play) user is performing– OS designed mostly for ease of use, not for resource utilization• Some users interface to mainframe or minicomputer– OS is designed to maximize resource use (CPU, memory, I/O)• Some users set at workstations connected to networks of servers– Dedicated and shared resources– OS compromises between individual usability and resource utilization• Handheld systems have OS designed for individual usability• Embedded systems designed to run without user interventionAugust 06 16CMSC412 Set 1System View of a Computer• OS is program most involved with the hardware• OS is a resource allocator– Manages all resources– Decides between conflicting requests for efficient and fair resource use• OS is a control program– Controls execution of programs to prevent errors and improper use of the computerAugust 06 17CMSC412 Set 1Defining Operating Systems• No universally accepted definition• “Everything a vendor ships w hen you order an operating system ” is good approxim ation– But varies wildly• “The one program running at all tim es on the com puter” is the one generally used in this course– This is the kernel– Everything else is either a system program (ships with the operating system) or an application programAugust 06 18CMSC412 Set 1Computer System Organization• Computer-system operation– One or more CPUs, device controllers connect through common bus providing access to shared memory– Concurrent execution of CPUs and devices competing for memory cyclesAugust 06 19CMSC412 Set 1Computer Startup and Execution• bootstrap program is loaded at power-up or reboot– Typically stored in ROM or EEPROM, generally known as firmware– Initializes all aspects of system– Loads operating system kernel and starts execution• Kernel runs, waits for event to occur– Interrupt from either hardware or software• Hardware sends trigger on bus at any time• Software triggers interrupt by system call• Stops current kernel execution, transfers execution to fixed location– Interrupt service routine executes and resumes kernel where interrupted– Usually a service routine for
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