An active entity in an operating system is referred to as what?

An active entity in an operating system is referred to as a process because it represents an individual instance of a program in execution. A process includes the program code (often called text section), its current activity (represented by the value of the program counter and the contents of the processor's registers), and a stack, which contains temporary data such as function parameters, return addresses, and local variables.

Processes are crucial since they are the unit of resource allocation and scheduling within an operating system. Each process can execute independently and can be managed separately, allowing for multitasking and efficient utilization of CPU resources. Their active nature is indicated by their ability to perform work, which includes executing instructions, utilizing memory, and communicating with other processes.

In contrast, while functions, threads, and resources are also relevant concepts in the context of operating systems, they do not encapsulate the notion of an active entity in the same way. Functions are blocks of code that can be executed, threads represent smaller units of a process that can run concurrently, and resources encompass all the entities that the system can manage, such as memory, CPU time, and I/O devices. Thus, the term that best fits the description of an active entity is a process.