CMPT%20300:%20Operating%20Systems

1
CMPT 300 Operating Systems

• Review
• THIS REIVEW SHOULD NOT BE USED AS PREDICTORS OF
  THE ACTUAL QUESTIONS APPEARING ON THE FINAL EXAM.

2
What Will Be in The Final Exam?

• Concepts Definitions
• E.g., working set, aging
• Conditions Assumptions
• E.g., conditions of deadlocks?
• Pros Cons
• E.g., contiguous allocation Vs. linked list
• Events
• E.g., interrupt, page fault
• Algorithms
• E.g., Petersons solution, scheduling algorithms
• Data structures
• E.g., page table, process table

3
How to Go Over the Materials?

• Read text book and lecture notes
• Reading lecture notes only may not be enough
• Understand the concepts and definitions
• Keep thinking
• Relation between concepts
• E.g., DMA Vs. paging
• Why does an algorithm work here?
• Extensions and implications of principles
• E.g., strict alternation, Petersons solution

4
Ch01 Overview of OS

• OS structures
• Hardware
• CPU, memory, disk, bus, DMA
• Basic concepts
• Process (thread), deadlock, I/O, file system
• Sections not covered in the final exam
• 1.2. History of operating systems
• 1.3. The operating system zoo

5
Ch02 Processes And Threads

• Processes
• Differences with programs?
• States and transitions
• Process table
• Fork()
• Threads
• Differences with processes? Pros Cons?
• Kernel space Vs. user space implementation
• Typical applications ( I/O and CPU mixed task)

6
Ch02 (Cont.)

• Inter-process communication
• Race condition
• Critical region Mutual exclusion
• Busy waiting
• Disable interrupts, lock variables, strict
  alternation, Petersons solution
• Sleep wakeup calls, mutexes, semaphores,
  monitors, message passing
• Classical IPC problems
• How to apply mechanisms to solve problems?

7
Ch02 (Cont.)

• Scheduling
• Preemptive Vs. non-preemptive
• Benchmarks turnaround time, throughput,
  response time
• FCFS, SJF, RR, MQ, etc
• Three-level scheduling
• Sections not covered in exam
• 2.5.4 real-time scheduling
• 2.5.5 policy Vs. mechanism

8
Ch03 Deadlocks

• Conditions for deadlock
• Solutions for deadlock problem
• Ostrich algorithm
• Detection and recovery
• Avoidance
• Prevention
• Other issues
• Two-phase locking
• Starvation

9
Ch04 Memory Management

• Basic management
• Fixed partitions (single queue Vs. multiple
  queues)
• Degree of multi-programming
• Relocation and protection (base limit
  registers)
• Bitmaps Vs. linked list
• Swapping
• Scenario memory not enough
• External fragmentation (memory compaction)
• Virtual memory
• Paging pages Vs. page frames, page faults
• MMU, TLB, page table, page table entry

10
Ch04 (Cont.)

• Page replacement algorithms
• NRU, FIFO, second chance, clock, LRU, NFU, aging
• Working set, WSClock algorithm
• Assumptions, relations
• Modeling
• Beladys anomaly
• Stack algorithm
• Design issues
• Global Vs. local, page sizes, shared pages,
  copy-on-write

11
Ch04 (Cont.)

• Implementation
• Page fault handling, backing stores
• Segmentation
• Advantages
• Pure segmentation Vs. segmentation with paging
• Sections not covered in final exam
• 4.6.7, 4.7.3, 4.7.6, 4.8.3

12
Ch05 I/O

• Principles of I/O hardware
• Device controllers
• Memory-mapped I/O Vs. I/O port number
• DMA Vs. Interrupt
• Principles of I/O software
• Goals
• Three approaches
• I/O software layers
• Four layers
• Functions and relationship

13
Ch05 (Cont.)

• Disks
• Structure, format, layout
• Disk arm scheduling algorithms
• RAID
• Stable storage
• Clocks
• Basic work principle
• Sections not covered in the final exam
• In 5.4, CD-ROM, CD-R, DVD, 5.4.4
• 5.5.2, 5.5.3, 5.6-5.9

14
Ch06 File Systems

• Files
• Attributes, operations
• Memory-mapped files
• Directories
• Hierarchical directory
• Path name

15
Ch06 (Cont.)

• Implementations
• Files contiguous Vs. linked list, i-nodes
• Directories directory entry, long file name
• Shared files
• Disk space management
• Free list Vs. bitmap
• Reliability
• Backup full dump Vs. incremental dump
• Consistency check block Vs. directory check

16
Ch06 (Cont.)

• Performance
• Caching, block read ahead, reducing disk arm
  motion
• Sections not covered in final exam
• 6.3.8 log-structured file systems
• 6.4.1-6.4.4