Question

Execution of two or more programs by a single CPU is known as

• A. Multiprogramming
• B. Multiprocessing
• C. Timesharing
• D. CPU Sharing

Hint:

To distinguish between these operating system terms:
- Multiprogramming: One CPU, multiple programs loaded in memory (interleaved execution).
- Multiprocessing: Multiple CPUs, multiple programs executed simultaneously.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Operating systems use different processing techniques to maximize CPU utilization and throughput by executing multiple tasks efficiently.

Step 3: Detailed Explanation:
Let us define the processing techniques listed:
- Multiprogramming (A): This is a technique where two or more programs are loaded into the main memory (RAM) simultaneously, and a single CPU switches between them to execute them.
Because a single CPU can only execute one instruction at a time, it does not run the programs simultaneously.
Instead, it executes one program until that program encounters a delay (such as waiting for user input or an I/O operation).
The operating system then switches the CPU to execute the next program.
This rapid switching keeps the CPU busy, maximizing its utilization.
- Let us evaluate the other options:
- Multiprocessing (B): This technique uses two or more physical CPUs within a single computer system to execute multiple programs or instructions simultaneously.
- Timesharing (C): This is an extension of multiprogramming designed for multi-user systems.
The CPU allocates a tiny slice of time (quantum) to each user's program in rapid rotation, giving each user the illusion that they have sole use of the computer.
Therefore, the execution of multiple programs by a single CPU is called multiprogramming.

Step 4: Final Answer:
The execution of multiple programs by a single CPU is known as multiprogramming, matching Option (A).