Definition
Active Process
An active process is a process currently residing in main memory (RAM) and competing for or utilizing system resources (CPU, I/O).
Active processes are distinguished from suspended processes, which have been swapped out to secondary storage to free available physical memory.
Process States
Active States in the 7-State Model
In the Seven-State Process Model, active processes occupy the Ready, Running, or Blocked states. Suspended states (Ready/Suspend and Blocked/Suspend) are not active.
Resource Constraints
Memory Limit and Thrashing
The number of active processes is bounded by available physical memory. If too many processes are active simultaneously, the system may thrash, forcing the operating system to perform swapping to maintain performance.