How do operating systems ensure resource fairness among users?

Operating systems ensure resource fairness among users through process scheduling and resource allocation mechanisms.

Operating systems (OS) are designed to manage hardware and software resources on a computer, and one of their key responsibilities is to ensure that these resources are distributed fairly among users. This is achieved through a combination of process scheduling and resource allocation mechanisms.

Process scheduling is the method by which an OS decides which processes are given access to the system's resources at any given time. This is typically done using a scheduling algorithm, which can be based on a variety of factors such as priority, job size, or time of submission. The goal of the scheduling algorithm is to ensure that all processes get a fair share of the system's resources, while also maximising the system's overall efficiency.

For example, a common scheduling algorithm is the Round Robin algorithm, which allocates a fixed time slice to each process in the system. Once a process has used up its time slice, it is moved to the back of the queue and the next process is given access to the system's resources. This ensures that no single process can monopolise the system's resources, and that all processes get a fair chance to run.

Resource allocation is another important mechanism used by operating systems to ensure fairness. This involves deciding how the system's resources, such as CPU time, memory, and disk space, are distributed among the different processes. Again, this is typically done using an algorithm, which can be based on factors such as the priority of the process, the resources it requires, and the resources available.

For instance, an OS might use a resource allocation algorithm that gives priority to processes that require fewer resources, or to processes that have been waiting the longest. This helps to prevent resource starvation, where a process is unable to progress because it is constantly being denied the resources it needs.

In conclusion, operating systems use a combination of process scheduling and resource allocation mechanisms to ensure that all users get a fair share of the system's resources. These mechanisms are designed to maximise the system's overall efficiency, while also preventing any single user or process from monopolising the system's resources.