---
title: "Network OS vs distributed OS"
subject: "Distributed System"
chapter: 3
key: "semester_7/distributed_system:nos-vs-dos-diff"
source: https://www.bctengineer.com/q/semester_7/distributed_system/nos-vs-dos-diff
site: BCT Engineering
---

# Network OS vs distributed OS

Distributed System · Chapter 3: Operating System Support

- Asked in: Model question
- Video: [Network Operating System | Distributed Systems | Lec-11 | Bhanu Priya](https://www.youtube.com/watch?v=MtrcTjJfWSY) — Education 4u
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/distributed_system/nos-vs-dos-diff
- Whole chapter: https://www.bctengineer.com/md/semester_7/distributed_system/chapter-3

## Question

Differentiate between network operating system and distributed operating system.

## Short answer

A network OS runs on each node separately, users access remote resources explicitly (e.g., remote login), with little transparency. A distributed OS manages multiple computers as a single system, providing location transparency, process migration, global resource management, and high fault tolerance.

## Answer

A **network operating system (NOS)** runs on each computer of a network and lets users access remote resources explicitly (for example by logging in remotely or mounting a shared folder). A **distributed operating system (DOS)** manages a group of computers as one single system, so users see only one machine.

| Point | Network OS | Distributed OS |
|---|---|---|
| Image to user | Many separate machines | Single system image |
| Transparency | Little; user knows the location of resources | High: location, migration, replication transparency |
| Autonomy | Each node has its own OS and works independently | Nodes cooperate under one global OS |
| Resource management | Local, per machine | Global, with automatic load balancing |
| Process migration | Not supported | Supported |
| File access | Explicit (ftp, rlogin, mount) | Same naming for local and remote files |
| Fault tolerance | Low; failure of server affects its users | High; work moves to another node |
| Heterogeneity | Can handle different OSs | Usually needs the same OS or kernel on all nodes |
| Complexity and cost | Simple, cheap | Complex, harder to design |
| Examples | Windows Server, Unix with NFS, Novell NetWare | Amoeba, Mach, Sprite, Plan 9 |

In short, a NOS adds networking to ordinary operating systems, while a DOS replaces them with a global system.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. How do users see the system in a NOS compared with a DOS?
   A. NOS: single image; DOS: many machines
   B. Both: single image
   C. NOS: many separate machines; DOS: single system image
   D. Both: many machines
   Answer: C. A NOS users access remote resources explicitly; a DOS shows one machine. (Key point: Image to user)

2. Which feature is supported by a DOS but not a NOS?
   A. Remote login
   B. Process migration
   C. Mounting a shared folder
   D. File transfer
   Answer: B. A DOS has global resource management with load balancing and process migration. (Key point: Process migration)

3. Which statement about heterogeneity is correct?
   A. NOS can handle different OSs; DOS usually needs the same OS on all nodes
   B. DOS handles different OSs better
   C. Both need identical OSs
   D. Neither supports different hardware
   Answer: A. NOS nodes are autonomous; a DOS needs a common kernel. (Key point: Heterogeneity)

## Related in Distributed System

- [Context switching; distributed vs network OS](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Acontext-switch-dos) — Distributed System, chapter 3
- [Short note: Distributed OS](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Ados-note) — Distributed System, chapter 3
- [Autonomous vs distributed system](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Aautonomous-vs-distributed) — Distributed System, chapter 1
- [Operating system layers](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Aos-layers) — Distributed System, chapter 3
- [Centralized vs distributed; design issues](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Acentralized-vs-distributed) — Distributed System, chapter 1
- [Models of distributed system](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Amodels-of-ds) — Distributed System, chapter 1

## Related in other subjects

- [Multiprogramming, multiprocessing, distributed OS](https://www.bctengineer.com/question.md?key=semester_6%2Foperating_system%3Amultiprog-multiproc-distributed-os) — Operating System, chapter 1
- [OS abstraction, extended machine, system call](https://www.bctengineer.com/question.md?key=semester_6%2Foperating_system%3Aos-abstraction-system-call) — Operating System, chapter 1
- [Features of a typical operating system](https://www.bctengineer.com/question.md?key=semester_4%2Fmicroprocessor%3Afeatures-of-operating-system) — Microprocessor, chapter 6, asked 3×
- [Lumped vs distributed analysis, applications, protocols](https://www.bctengineer.com/question.md?key=semester_7%2Frf_and_microwave_engineering%3Alumped-distributed-protocols) — RF and Microwave Engineering, chapter 1