The Great Symbian

A deadlock can occur if the following four conditions hold

simultaneously:

1. Mutual exclusion: at least one resource must be held in a

nonsharable mode.

2. Hold and wait: a process must be holding at least one

resource and waiting to acquire additional resources held by

other processes.

3. No preemption: resources can’t be preempted.

4. Circular wait: there exists a set {P0, P1, …, Pn} of waiting

processes such that P0

is waiting for a resource that is held by

P1, P1 is waiting for a resource that is held by P2, …, Pn–1 is

waiting for a resource that is held by Pn, and Pn is waiting for a

resource that is held by P0.