CMPT 300: Operating Systems Course Summary THIS SUMMARY SHOULD NOT BE USED AS PREDICTORS OF THE ACTUAL QUESTIONS APPEARING ON THE FINAL EXAM.

2 lecture1_Overview+History Basic concepts Many contents covered in later lectures Kernel/user mode, mem hierarchy, cache, interrupts, multiprogramming, time-sharing

3 lecture2- Processes+Threads+Scheduling Processes Address space Memory layout Process state machine Fork() Threads Differences with processes? Pros & Cons? Typical applications Scheduling Preemptive Vs. non-preemptive throughput, response time FCFS, SJF, SRTF, RR, MLQ, Lottery, etc

lecture3+4-Synchronization Synchronization Too much milk example Critical region & Mutual exclusion Busy waiting Disable interrupts, lock & set Mutexes, semaphores, monitors Language constructs Classical IPC problems Bounded buffer, readers/writers, dining philosophers How to apply different mechanisms to solve problems? (semaphore solution vs. monitor solution) 4

5 Lecture5-Deadlocks 4 conditions for deadlock Deadlock detection: resource allocation graphs vs. Banker’s algorithm

Lecture6-Cache Memory hierarchy Principle of locality Cache: Tag, Index, Offset Direct-mapped vs. set-associative vs. fully- associative Compulsive, capacity, conflict misses Write-allocate, write-through vs. write-back 6

7 Lecture7-VirtualMemory Segmentation vs. paging Segmentation + paging; Multi-level paging Page tables and inverted page tables TLB User-space vs. kernel-space, system calls

8 Lecture8-PageReplacement Page swapping Belady’s anomaly FIFO, LRU, CLOCK, OPT Working set, WSClock algorithm Design issues Global vs. local page replacement Thrashing

9 Lecture9-IO Principles of I/O hardware Device controllers Direct I/O vs. Memory-mapped I/O Principles of I/O software Programmed I/O vs. Interrupt-driven I/O vs. DMA Precise interrupts I/O software layers Four layers Disks Structure and layout Disk arm scheduling algorithms RAID 0-1 Calculate disk size; disk performance

10 Lecture10-FileSystems Files Types, attributes, operations Directories Hierarchical directory Absolute vs. relative path names Implementations Contiguous, linked list, FAT, i-nodes Calculate max file size from I-node data structure Free disk space management Free list vs. bitmap File system caching

Lecture11-Security Secret Key vs. Public Key Crypto Passwords, salt Trap doors, login spoofing, buffer overflow Code injection attack, TENEX password problem Virus, worm, spyware, rootkits Mobile code security Protection domains, access control lists, capabilities Formal models: Bell-La Padula vs. Biba model Covert channels 11