Process Times

There are several times related to a process and we are going to cover each of them and going to learn why they exist and why they are important for CPU scheduling.

1. Arrival Time (AT)
   
   • Whenever a process gets into the “Ready State” or sometimes we call a “Ready Queue” and it is ready to be executed for its specified task.
2. Burst Time (BT)
   
   • Amount of CPU time taken by a process in order to finish its work is defined as burst time.
   • Problem: We cannot actually say that how much CPU time a process is going to take in the future.
3. Completion Time (CT)
   
   • The time at which the process completes its work or its execution is known as completion time.
4. Turn Around Time (TAT)
   
   • The difference between completion time and arrival time is known as a turn around time.
   • TAT = CT – AT
5. Waiting Time (WT)
   
   • The difference of turn around time and burst time is defined as waiting time.
   • WT = TAT – BT

All these time related to a process plays an important role when it comes to CPU Scheduling and all these times are considered by the scheduling algorithms.

Summary: In this post, we have covered sometimes related to a process and we have also understood why we need them and next thing after learning these times is to use these in scheduling algorithms and in order to do that, look at CPU Scheduling Algorithms.