Operating systems – multiprogramming outcomes: Which of the following is an expected benefit of multiprogramming compared with single-program execution?

Introduction / Context:
Multiprogramming lets the operating system keep several programs in memory at once, overlapping CPU and I/O so resources are not wasted. This increases system throughput and reduces idle time, a foundational concept for modern OS design and performance tuning.

Given Data / Assumptions:

• There are multiple independent jobs with CPU and I/O bursts.
• The OS can context switch among jobs when one blocks for I/O.
• Memory management is sufficient to hold more than one process.

Concept / Approach:

When one job waits for I/O, the CPU can execute another. Overlapping work in this way reduces idle CPU cycles, improves throughput, and, with appropriate scheduling, leads to better utilization across the system. Therefore, several positive outcomes occur together.

Step-by-Step Solution:

Verification / Alternative check:

Queueing models and OS metrics (CPU utilization, throughput, turnaround) consistently show higher values under multiprogramming compared to serial execution for mixed workloads.

Why Other Options Are Wrong:

a, b, c: Each is correct individually, but the most complete choice is all of the above.

e: Incorrect because multiprogramming does deliver these benefits.

Common Pitfalls:

Confusing multiprogramming (multiple in memory) with multiprocessing (multiple CPUs); overlooking that high context-switch overhead or memory contention can limit gains if not tuned properly.

Final Answer:

All of the above