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Operating Systems. Operating Systems. Midterm review: closed book multiple choice chapters 1 to 9. Chapter 1&2: The Basics. kernel mode or kernel space user mode or user space system call: user mode program invokes kernel mode functionality. Chapter 2: Operating System Architectures.
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Operating Systems Operating Systems Midterm review: closed book multiple choice chapters 1 to 9
Chapter 1&2: The Basics • kernel mode or kernel space • user mode or user space • system call: • user mode program invokes kernel mode functionality COP 5994 - Operating Systems
Chapter 2: Operating System Architectures • monolithic • layered • micro-kernel • distributed COP 5994 - Operating Systems
Chapter 3: Process end begin COP 5994 - Operating Systems
Execution context Process Control Blocks COP 5994 - Operating Systems
Context Switch COP 5994 - Operating Systems
Interrupt Processing COP 5994 - Operating Systems
Chapter 4: Thread vs. Process COP 5994 - Operating Systems
Combining User- and Kernel-level Threads m-to-n thread mapping: COP 5994 - Operating Systems
Chapter 5: Concurrent execution • System has more than one thread/process • either independent or in cooperation: • mostly independent • occasionally need to communicate or synchronize COP 5994 - Operating Systems
Mutual exclusion algorithm • General structure of process Pi(vs. Pj) do { entry protocol critical section exit protocol remainder section } while (true); COP 5994 - Operating Systems
Semaphore • Software construct to enforce mutual exclusion • Contains a protected variable: • accessed via wait and signal commands PV • binary semaphore: 0 or one • counting semaphore COP 5994 - Operating Systems
Chapter 6: Monitor • Programming language construct • Contains data and procedures needed to access shared resource • resource accessible only within the monitor • Supports: • mutual exclusion • synchronization • Dijkstra, Brinch-Hansen, Hoare COP 5994 - Operating Systems
Chapter 7: Conditions for Deadlock • Mutual exclusion • resource accessed by only one process at a time • Hold-and-wait-for • process holds resource(s) while waiting for other resource(s) • No-preemption • system cannot remove resource from the process until the process has finished using the resource • Circular-wait • processes are in a “circular chain” where each process is waiting for resource(s) of next process in chain COP 5994 - Operating Systems
Chapter 8: Processor scheduling COP 5994 - Operating Systems
Scheduling Criteria • CPU utilization • keep the CPU as busy as possible • Throughput • # of processes that complete per time unit • Turnaround time • amount of time to execute a process • Waiting time • time a process has been waiting in the ready queue • Response time • time from request until first response is produced COP 5994 - Operating Systems
Chapter 9: Memory COP 5994 - Operating Systems
Evolution of memory organization COP 5994 - Operating Systems
Preparation: • Self review questions • Chapter exercises COP 5994 - Operating Systems