TAILIEUCHUNG - Lecture Operating system concepts - Module 7

In the previous chapter, we looked at UML class diagrams. This chapter continues the study of the static view of software by looking at typical patterns found in class diagrams. These patterns recur in many designs; by learning and using them you are reusing the collective experience of many software developers. | Module 7: Deadlocks System Model Deadlock Characterization Methods for Handling Deadlocks Deadlock Prevention Deadlock Avoidance Deadlock Detection Recovery from Deadlock Combined Approach to Deadlock Handling Operating System Concepts The Deadlock Problem A set of blocked processes each holding a resource and waiting to acquire a resource held by another process in the set. Example System has 2 tape drives. P1 and P2 each hold one tape drive and each needs another one. Example semaphores A and B, initialized to 1 P0 P1 wait (A); wait(B) wait (B); wait(A) Operating System Concepts Bridge Crossing Example Traffic only in one direction. Each section of a bridge can be viewed as a resource. If a deadlock occurs, it can be resolved if one car backs up (preempt resources and rollback). Several cars may have to be backed upif a deadlock occurs. Starvation is possible. Operating System Concepts System Model Resource types R1, R2, . . ., Rm CPU cycles, memory space, I/O devices Each resource

• Hệ điều hành
• Operating system concepts
• Lecture Operating system concepts
• Operating system
• Computer system organization
• Operating system structure
• Operating system services
• Operating system structures
• Operating system design
• Hệ điều hành
• Operating System Debugging
• Operating System Generation
• Types of System Calls
• Computer system structures
• File system interface
• File system implementation
• Computer system architecture
• The Linux system