DEADLOCKS PDF MIDTERM - OPERSYS 3RD YEAR 1ST SEM

1. Deadlocks
 Introduction to Deadlocks
 Deadlock Prevention
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*Property of STI J0024
Deadlock
 condition wherein a set of processes cannot continue executing because each
process is waiting for a resource that is being held or used by another process
within the set
Figure 7.1 Example of a Deadlock
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*Property of STI J0024
Figure 7.2 Example of a Deadlock Using a Wait-For Graph
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*Property of STI J0024
Figure 7.3 Traffic Deadlock
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2. *Property of STI J0024
Necessary conditions for a deadlock:
 Mutual exclusion
 Hold and wait
 No preemption
 Circular wait
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*Property of STI J0024
Deadlocks can be prevented by removing at least one of the four
conditions:
 Removing the mutual exclusion condition
 Removing the hold and wait condition
 Removing the no preemption condition
 Removing the circular wait condition
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