31436 Systems Software and Networks 31510 Operating Systems

1
31436 Systems Software and Networks31510
Operating Systems

• Review

2
Operating Systems

• System Software
• User/Computer Interface
• Resource Manager

3
Process Management

• Process states
• running, ready, blocked, new, exit
• Process control
• process creation events
• process switch
• mode switch

4
Mutual Exclusion

• Requirements for mutual exclusion
• mutual exclusion, independence, no deadlock, no
  delay, no assumptions, limited time
• Software approaches
• turn, flag
• Hardware approaches
• test and set instruction, exchange instruction
• OS approaches
• semaphores

5
Deadlock

• Deadlock conditions
• mutual exclusion, hold and wait, no preemption,
  circular wait
• Deadlock prevention
• dissatisfying deadlock conditions
• Deadlock avoidance
• not to grant any request which will lead to
  circular wait
• Deadlock detection

6
Memory Management

• Simple paging
• Simple segmentation
• Virtual memory paging
• Virtual memory segmentation

7
Scheduling - Processor Management

• Long-term scheduling
• Medium-term scheduling
• Short-term scheduling
• FCFS, RR, SPN

8
I/O Management

• Programmed I/O
• Interrupt-driven I/O
• DMA
• Disk scheduling
• seek time
• rotational delay
• access time
• Disk scheduling policies
• FIFO, SSTF, SCAN, C-SCAN

9
File Management

• File allocation
• contiguous, chained, and indexed allocation
  methods