This document discusses distributed operating systems (DOS), which utilize multiple processors to manage real-time applications and data processing. It details different types of distributed systems, their architectures, and applications, including file and computer server systems, as well as design issues like scalability and security. Additionally, the document outlines approaches for detecting distributed deadlocks, including centralized, hierarchical, and distributed methods.

1. Advanced Operating Systems
I MCA- II SEMESTER
SUBJECT CODE : P22MCACC22
UNIT – II
Distributed OS
Presented By
S.Vijaya Lakshmi B.E(CSE)
Assistant Professor,
Department of Computer Science,
Sri Sarada Niketan College for Women,Karur.

2. Distributed Operating System
 A distributed operating system (DOS) is an
essential type of operating system.
Distributed systems use many central
processors to serve multiple real-time
applications and users.
 As a result, data processing jobs are
distributed between the processors.

3. Distributed OS Types
 Client-Server Systems
 Peer-to-Peer Systems
 Middleware
 Three-tier
 N-tier

4. Server systems can be divided into two parts:
Computer Server System
This system allows the interface, and the client
then sends its own requests to be executed as an
action. After completing the activity, it sends a
back response and transfers the result to the
client.
File Server System
It provides a file system interface for clients,
allowing them to execute actions like file creation,
updating, deletion, and more.

5. Architecture of a Distributed OS

6. Applications of Distributed Operating
System
 Internet Technology
 Distributed databases System
 Air Traffic Control System
 Airline reservation Control systems
 Peep-to-peer networks system
 Telecommunication networks
 Scientific Computing System
 Cluster Computing
 Grid Computing
 Data rendering

7. Design issues of distributed system
 Heterogeneity
 Openness
 Scalability
 Security
 Failure Handling
 Concurrency
 Transparency

8. Communication Model
 Communication in distributed systems
is always based on low-level message
passing as offered by the underlying
network.
 Expressing communication through
message passing is harder than using
primitives based on shared memory, as
available for non-distributed platforms.

9. Network Communications Models
 Point-to-point.
 Client-server.
 Publish-subscribe.

10. What is Distributed Deadlock?
 Distributed deadlocks can occur when distributed
transactions or concurrency control are utilized in
distributed systems.
 It may be identified via a distributed technique like edge
chasing or by creating a global wait-for graph (WFG)
from local wait-for graphs at a deadlock detector.

11. Approaches
 Centralized Approach
 Hierarchical Approach
 Distributed Approach

12. Approaches to detect deadlock in the
distributed system
Centralized Approach
 Only one resource is responsible for detecting deadlock in the
centralized method, and it is simple and easy to use.
 Still, the disadvantages include excessive workload on a single
node and single-point failure
 The entire system is dependent on one node, and if that node
fails, the entire system crashes, making the system less reliable.

13. Hierarchical Approach
 In a distributed system, it is the integration of
both centralized and distributed approaches to
deadlock detection.
 In this strategy, a single node handles a set of
selected nodes or clusters of nodes that are in
charge of deadlock detection.

14. Distributed Approach
 In the distributed technique, various nodes work to
detect deadlocks.
 There is no single point of failure as the workload is
equally spread among all nodes.
 It also helps to increase the speed of deadlock detection

15. Thank You