Operating System - Distributed Operating Systems

A Distributed Operating System (DOS) is an operating system that manages a collection of independent computers and makes them work together as if they are a single system. Instead of one computer performing all tasks, multiple computers connected through a network share resources, data, and processing work.

Basic Idea

In a traditional operating system, all processes run on one computer. In a distributed operating system, many computers cooperate and communicate with each other. Users do not need to know which computer is executing their program because the system hides this complexity. This concept is called transparency.

Key Characteristics

  1. Resource Sharing
    Computers share hardware resources such as processors, storage devices, printers, and memory across the network.

  2. Transparency
    The system appears as one unified computer system. Users access files and programs without knowing their physical location.

  3. Concurrency
    Multiple processes run simultaneously on different machines, improving overall performance.

  4. Scalability
    New computers can be added to the network without major changes to the system.

  5. Fault Tolerance
    If one machine fails, other machines continue working, ensuring system reliability.

Components of a Distributed Operating System

Node
Each computer connected in the distributed system is called a node.

Communication Network
Nodes communicate through network connections using message passing.

Distributed File System
Files are stored across multiple machines but appear as a single file system to users.

Process Management
Processes may execute on different machines while coordinating with each other.

Working Principle

When a user submits a task, the distributed operating system divides the work among available machines. The system selects the best node based on workload, processing power, or resource availability. After execution, results are combined and presented to the user as if processed by one computer.

Advantages

Improved performance because tasks are shared among many computers.
High reliability since system failure is less likely.
Efficient resource utilization.
Supports large-scale computing environments.

Disadvantages

Complex system design and management.
Network dependency can affect performance.
Security challenges due to multiple connected systems.

Examples

Cluster computing systems
Cloud computing platforms
Distributed databases
Large-scale scientific computing environments

Real-Life Applications

Online banking systems
Search engines handling millions of requests
Airline reservation systems
Cloud services that run applications across many servers

A distributed operating system plays an important role in modern computing by enabling powerful, scalable, and reliable systems using multiple interconnected computers.