TAILIEUCHUNG - Lecture Operating systems: Lesson 6 - Dr. Syed Mansoor Sarwar

Lecture Operating systems: Lesson 6 - Dr. Syed Mansoor Sarwar. The main topics covered in this lesson include: process scheduling concepts; process creation and termination; process management in UNIX/Linux—system calls: fork, exec, wait, exit; sample codes; . | Operating Systems Lecture 6 Agenda for Today Review of previous lecture Process scheduling concepts Process creation and termination Process management in UNIX Linux system calls fork exec wait exit Sample codes Recap of the lecture 28 April 2022 Copyright Virtual University of Pakistan Review of Lecture 5 Browsing the UNIX Linux directory structure Useful UNIX Linux commands Process concept attributes states types CPU- and I O-bound PCB OS queues CPU scheduling and context switch 28 April 2022 Copyright Virtual University of Pakistan Schedulers Long term scheduler Short term scheduler Medium term scheduler 28 April 2022 Copyright Virtual University of Pakistan Queues in a Computer System 28 April 2022 Copyright Virtual University of Pakistan Long Term Scheduler Long-term scheduler or job scheduler selects processes from the job pool to be brought into the ready queue. Long-term scheduler is invoked very infrequently seconds minutes may be slow . The long-term scheduler controls the degree of multiprogramming. More processes smaller percentage of time each process is executed 28 April 2022 Copyright Virtual University of Pakistan Short Term Scheduler Short-term scheduler or CPU scheduler selects which process should be executed next and allocates it the CPU through the dispatcher. Short-term scheduler is invoked very frequently milliseconds must be fast . Invoked when following events occur CPU slice of the current process finishes Current process needs to wait for an event Clock interrupt I O interrupt System call 28 April 2022 Copyright Virtual University of Signal Pakistan Medium Term Scheduler Also known as swapper Selects an in-memory process and swaps it out to the disk temporarily Swapping decision is based on several factors Arrival of a higher priority process but no memory available Poor mix of jobs 2022 28 April Memory request of Virtual Copyright a process University of cannot be met Pakistan Addition of Medium Term Scheduling 28 April 2022 Copyright .

• Hệ điều hành
• Lecture Operating systems
• Bài giảng Hệ điều hành
• Operating systems
• Process scheduling concepts
• Long term scheduler
• Context switch time
• Lecture Advanced Operating Systems
• Advanced Operating Systems
• Bài giảng Hệ điều hành nâng cao
• Server operating systems
• Multiprocessor operating systems
• PC operating systems
• Main frame operating systems
• Real time operating systems
• Structure of operating systems
• Distributed operating systems
• Memory management
• Embedded systems
• Modern operating systems
• Evolution of operating systems
• Memory protection
• File systems
• Characteristics of real time operating systems
• Real time scheduling
• Hệ điều hành
• Distributed systems
• Network operating systems
• Resource management
• User programs
• Computing environments
• Monolithic structure
• Implementing processes
• Process synchronization
• Scheduling policies
• Deadlock detection
• Handling deadlocks
• Message passing
• Implementing message passing
• Virtual memory
• Virtual memory manager
• File operations
• Distributed control algorithms
• Election algorithms
• Distributed system security
• Message security
• Networking essentials plus
• Lecture Networking essentials plus
• Novell operating systems
• Microsoft network operating systems
• Operating system
• Operating system concept
• Operating systems design
• Operating systems capabilities
• Network operating system
• Operating system structures
• Operating system design
• Operating system services
• Internalsand design principles
• Computer system
• Operating system objectives