Chapter 1: Process If Process

Running Processes and Scheduling

Definition of Running Process

• A running process is defined as a process that is currently executing on the CPU. It is considered a correct answer in the context of operating systems and process management.

Ready State Processes

• Ready State: Processes that are in the ready state are waiting for the CPU to execute them.

  • These processes are not actively executing but are prepared to be executed by the CPU.

  • They are simply waiting for the operating system's scheduler to allocate CPU time to them.

Scheduling Mechanism

• Operating System Scheduler: The component of the operating system responsible for determining which process in the ready state is to be executed next on the CPU.

• When a process in the ready state gets selected:

  • The process will begin its execution from the instruction indicated by its program counter.

  • The program counter points to the next instruction to be executed in the process's binary code.

Resumption of Execution

• Upon being scheduled on the CPU, the resumption of execution can occur in two scenarios:

  • First Instruction Execution:

  • If the process is being executed for the first time (newly created), it will start from the very first instruction in the process's binary.

  • Random Instruction Execution:

  • If the process was previously interrupted (e.g., by the scheduler or due to needing to wait on an I/O operation or an external event), it will continue execution from the instruction it was last executing before the interruption.

  • This behavior highlights the interrupt handling capabilities of operating systems, where they save the state of a process to allow resumption later.