Condition for Deadlock

Here, we want to share two conditions for a deadlock to occur.

Condition for Deadlock

https://upload.wikimedia.org/wikipedia/commons/2/2f/Mutual_exclusion_example_with_linked_list.png

Mutual Exclusion Model

1. Mutual exclusion:

Automatically holds for printers and other non-sharables.

Shared entities (read only files) don't need mutual exclusion (and aren’t susceptible to deadlock).

Prevention not possible, since some devices are intrinsically non-sharable.

http://www.cs.fsu.edu/~baker/cop5611.S03/graphics/basicdeadlock2.gif

Hold And Wait Model

2. Hold and wait:

must guarantee that whenever a process requests a resource, it does not hold any other resources.
Require process to request and be allocated all its resources before it begins execution, or allow process to request resources only when the process has none.
Low resource utilization; starvation possible.

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