Processor point of view of OS

Processor point of view: At a certain point, the processor is executing instructions  from the portion of main memory containing the monitor.These instructions  cause the next job to be read into another portion of main memory. Once  a job has been read in, the processor will encounter a branch instruction in the  monitor that instructs the processor to continue execution at the start of the  user program.The processor will then execute the instructions in the user program  until it encounters an ending or error condition. Either event causes the processor to fetch its next instruction from the monitor program. Thus the  phrase “control is passed to a job” simply means that the processor is now  fetching and executing instructions in a user program, and “control is returned  to the monitor” means that the processor is now fetching and executing instructions  from the monitor program.