In operating systems and networking, what is meant by a distributed system and how is it conceptually defined?

Introduction / Context:
Distributed systems are at the heart of modern computing. When you use cloud services, social networks, or large web applications, you interact with many machines that work together behind the scenes. Operating systems and distributed systems courses introduce a conceptual definition that highlights independence of computers, network communication, and the illusion of a single system. This question checks whether you know that standard textbook definition.

Given Data / Assumptions:

• There are multiple computers connected by a communication network.
• Each computer has its own processor and memory and can run its own local operating system.
• Users and applications access shared resources or services provided by the group of machines.

Concept / Approach:
A distributed system is usually defined as a collection of independent computers that appears to the users as a single coherent system. Independence means that each node can fail or be restarted without directly crashing all other nodes, and that the machines do not share a single physical memory or clock. Coherence means that software layers on top hide many of these complexities and present integrated services such as distributed file systems, databases, or computation frameworks. The operating system, middleware, and network protocols cooperate to manage communication, synchronization, naming, consistency, and fault tolerance across nodes.

Step-by-Step Solution:
Step 1: Identify that a distributed system must involve more than one computer connected by a network.Step 2: Recall the textbook phrase describing a distributed system as a collection of independent computers that appears as a single system.Step 3: Check which option matches both independence of nodes and unified view for users.Step 4: Option A clearly mentions a collection of independent computers, a single coherent system view, and cooperation over a network.Step 5: The other options either describe single computers or specific applications rather than the general concept.

Verification / Alternative check:
Common examples help verify the definition. Distributed file systems like NFS or HDFS, distributed databases, and cloud clusters such as Kubernetes all involve many machines that collectively offer services. From the user perspective, these services often look like a single large system, even though internally the work is spread across multiple nodes. This matches the idea described in option A.

Why Other Options Are Wrong:
Option B talks about a single mainframe with no networking, so it is not distributed in the sense of independent cooperating computers.Option C describes a stand alone desktop computer, which again is not distributed.Option D mentions a specific peer to peer application type, which is only one example and does not capture the full meaning of distributed systems.

Common Pitfalls:
Some learners think that any networked system is automatically a distributed system. The key ideas are independence of nodes and the abstraction that hides distribution from users. Another pitfall is to confuse distributed systems with parallel systems that use tightly coupled processors and shared memory. Although both involve multiple processing units, the architecture and programming models differ.

Final Answer:
The correct answer is A collection of independent computers that appear to users as a single coherent system and cooperate over a network to share resources and services.