In operating systems, computer systems that can run more than one process concurrently are called what?

Introduction / Context:
In operating systems, one of the key goals is to improve processor utilization by keeping the CPU busy with useful work. To achieve this, operating systems often allow more than one process to reside in memory and appear to execute at the same time. Understanding the correct term for such systems is very important in basic computer science, especially in the study of operating systems and process management.

Given Data / Assumptions:

• We are talking about computer systems and operating systems.
• The question focuses on systems that run more than one process concurrently.
• The options mention terms like multiprocessing, multiprogramming, real time, and batch processing.
• Concurrency here means that multiple processes are in memory and logically make progress during the same period.

Concept / Approach:
The key idea is to distinguish between several related but different terms. Multiprogramming refers to having multiple programs in memory at the same time, with the CPU switching between them. Multiprocessing refers to having more than one physical processor. Real time systems focus on time critical responses. Batch processing groups jobs and runs them without interaction. Since the question talks about running more than one process concurrently on a single CPU system, the correct concept is multiprogramming.

Step-by-Step Solution:
Step 1: Identify the core phrase in the question, which is “running more than one process concurrently”.Step 2: Recall that in multiprogramming, several programs are loaded into memory and the CPU switches between them, creating the effect of concurrent execution.Step 3: Recognize that multiprocessing is about multiple CPUs rather than the number of processes alone.Step 4: Note that real time systems and batch processing describe timing and job handling styles, not specifically concurrent processes in memory.Step 5: Conclude that the term which directly matches the given description is multiprogramming systems.

Verification / Alternative check:
A standard textbook definition of multiprogramming is that it is an operating system capability that allows more than one program to be loaded into memory and executed by interleaving their instructions. This matches the phrase in the question word for word. By contrast, multiprocessing requires multiple CPUs and is a hardware attribute. This cross check confirms that multiprogramming is the intended answer for systems running several processes concurrently on one processor.

Why Other Options Are Wrong:
Multiprocessing systems use two or more processors and focus on parallel hardware rather than simply running multiple processes in memory. Real time systems focus on strict timing constraints and deadlines, which is a different property. Batch processing systems process groups of jobs without interactive input, and may or may not involve concurrency in the sense described. Therefore these options do not best describe the specific situation in the question.

Common Pitfalls:
A common mistake is to confuse multiprogramming with multiprocessing because both seem to involve multiple activities. Another pitfall is assuming that any system executing multiple jobs must be batch processing, even though batch is more about how jobs are submitted. Students sometimes ignore the subtle difference between hardware level parallelism and operating system level interleaving, which leads to incorrect choices.

Final Answer:
The correct answer is Multiprogramming systems, because they are specifically designed to keep more than one process in memory and allow them to run concurrently by sharing CPU time.