Which statement about multiprocessing and multiprogramming is false?

Which statement about multiprocessing and multiprogramming is false?

• A. Multiprogramming switches back and forth between programs during processing.
• B. Multiprocessing allows the sharing of a central memory during processing.
• C. Multiprocessing allows multiple programs to be executed at exactly the same time.
• D. Multiprogramming allows multiple programs to be executed at exactly the same time.

Answer: (D)

The key idea is how parallelism is achieved: time-sharing versus true parallel execution. Multiprogramming relies on a single processor and the operating system switches rapidly between programs to keep the CPU busy; you don’t get two programs running at exactly the same moment, you get them to share the CPU’s time slices. Multiprocessing, on the other hand, uses multiple processors or cores, so several programs can genuinely run at the same time. So saying that multiprogramming allows multiple programs to be executed at exactly the same time is false. The other statements fit with how the two concepts operate: multiprogramming involves switching between programs, multiprocessing often uses shared main memory to allow communication and coordination, and multiprocessing can run programs in parallel on different processors.

The key idea is how parallelism is achieved: time-sharing versus true parallel execution. Multiprogramming relies on a single processor and the operating system switches rapidly between programs to keep the CPU busy; you don’t get two programs running at exactly the same moment, you get them to share the CPU’s time slices. Multiprocessing, on the other hand, uses multiple processors or cores, so several programs can genuinely run at the same time. So saying that multiprogramming allows multiple programs to be executed at exactly the same time is false. The other statements fit with how the two concepts operate: multiprogramming involves switching between programs, multiprocessing often uses shared main memory to allow communication and coordination, and multiprocessing can run programs in parallel on different processors.