What is a working set?

A working set is a concept used in computer science to represent the set of resources or data that a computer program is actively using at a given time. This can include variables, files, memory, and other resources that the program needs to perform its tasks.

The working set of a program can change over time as the program executes, with different parts of the program's data and resources becoming more or less active depending on the program's current state and the inputs it receives. Keeping track of a program's working set can help optimize its performance by ensuring that the most frequently used resources are readily available in memory, reducing the need for costly disk or network access.

In some operating systems, the working set of a program may be actively managed by the operating system, through techniques such as memory paging, caching, and prefetching. By efficiently managing a program's working set, an operating system can improve the program's overall performance and responsiveness.