ensure that simultaneous updates to the same part of the list cannot occur. The term mutual exclusion is also used in reference to the simultaneous writing of a memory address by one thread while the aforementioned memory address is being manipulated or read by one or more other threads. Problem description The problem which mutual exclusion addresses is a problem of resource sharing: how can a software system control multiple processes' access to a shared resource, when each process needs exclusive control of that resource while doing its work? The mutual-exclusion solution to this makes the shared resource available only while the process is in a specific code segment called the critical section. It controls access to the shared resource by controlling each mutual execution of that part of its program where the resource would be used. A successful solution to this problem must have at least these two properties: It must implement mutual exclusion: only one process can be in the critical section at a time. It must be free of deadlocks: if processes are trying to enter the critical section, one of them must eventually be able to do so successfully, provided no process stays in the critical section permanently. Deadlock freedom can be expanded to implement one or both of these properties: Lockout-freedom guarantees that any process wishing to enter the critical section will be able to do so eventually. This is distinct from deadlock avoidance, which requires that some waiting process be able to get access to the critical section, but does not require that every process gets a turn. If two processes continually trade a resource between them, a third process could be locked out and experience resource starvation, even though the system is not in deadlock. If a system is free of lockouts, it ensures that every process can get a turn at some point in the future. A k-bounded waiting property gives a more precise commitment than lockout-freedom. Lockout-freedom ensures every process can access the critical section eventually: it gives no guarantee about how long the wait will be. In practice, a process could be overtaken an arbitrary or unbounded number of times by other higher-priority processes before it gets its turn. Under a k-bounded waiting property, each process has a finite maximum wait time. This works by setting a limit to the number of times other processes can cut in line, so