Client-Server Model

In the client-server model, one or more powerful computers called servers provide services or resources to other computers called clients. The clients make requests to the servers for resources or services, and the servers respond by providing those resources or services. This model is commonly used in situations where there is a central authority or a need for a centralized database or application.

OR

The client-server model is like a restaurant where the server (waiter) takes your order (request) and brings you your food (response). In this case, the server is like a powerful computer that provides resources or services (like web pages or emails) to other computers called clients (like your laptop or phone). The client makes a request to the server, and the server responds by providing the requested resource or service.


For example, when you browse the web, your computer acts as a client that requests web pages from web servers located around the world. When you send an email, your email client communicates with a mail server to send and receive messages.

Peer to Peer Model

In the P2P model, computers on the network (called peers) communicate and share resources directly with each other, without the need for a central server. Each peer can act as both a client and a server, and all peers have equal status. This model is commonly used for file sharing and other distributed computing applications.

OR

The peer-to-peer model is like a potluck dinner where everyone brings a dish to share with others. Each person (peer) brings something to the table and takes what they want from others. In this case, each computer on the network can act as both a client and a server, and they communicate and share resources (like files) directly with each other without the need for a central server or authority.

For example, when you use a P2P file-sharing application like BitTorrent, you are downloading files directly from other users’ computers, and you are also sharing files from your own computer with others on the network. In this model, there is no central authority controlling the network or the resources being shared.

Difference between Client Server Model and Peer to Peer Model

CategoryClient-Server ModelPeer-to-Peer Model
DefinitionA centralized model in which clients request services from a server.A decentralized model in which each node in the network can act as both a client and a server.
ArchitectureTwo-tier architecture with separate client and server processes.Flat architecture with all nodes having equal roles.
CommunicationCommunication is typically one-to-one, with the client sending a request to the server and receiving a response.Communication is typically one-to-many, with each node communicating directly with other nodes in the network.
Resource ControlServer has centralized control over shared resources, such as databases or files.Each node has control over its own resources, with no central control.
ScalabilityScalability can be limited by the processing power and bandwidth of the server.Scalability is more flexible, as new nodes can easily be added to the network.
ReliabilitySingle point of failure in the server.More resilient to failures, as nodes can continue to communicate even if some nodes fail.
SecurityCentralized security measures can be implemented to protect resources.Security measures must be implemented on each node individually.
Data StorageData is stored on the server and accessed by clients.Data can be stored on any node in the network, with each node responsible for managing its own data.
Network TrafficNetwork traffic is concentrated on the server.Network traffic is distributed across all nodes in the network.
ExamplesWeb applications, email servers, file servers.File-sharing networks, BitTorrent, blockchain networks

OS-2022

Q-1.

(a) Write are the functions of operating systems? write a note on multi programmed operating systems ?

(b) Distinguish between client server and peer to peer model of distributed systems .

Q-2.

(a) With a Neat Sketch, Describe the services that an Operating System provides to users, processes and other systems.

(b) What is meant by Storage Structure? Discuss Storage Hierarchy.

(c) Write the Advantages and Disadvantages of using the same system call interface for manipulating both Files and Devices.

Q-3.

(a) What are the criteria for evaluating the CPU scheduling algorithms? Why do we need it?

(b) Define process. Explain various steps involved in change of a process state with process state neat transition diagram.

Q-4.

(a) What is synchronization? Explain how semaphores can be used to deal with n-process critical problem.

(b) Define a thread. Give the benefits of multithreading. What resources are used when a thread is created?

Q-5.

(a) How dose deadlock avoidance differ from deadlock prevention? Write about deadlock avoidance algorithm in detail.

(b) Different between external fragmentation and internal fragmentation. How to solve the fragmentation using paging?

Q-6.

(a) What is the purpose of paging the page table? Consider the following page reference string 1,2,3,4,5,1,2,3,4,5 for a memory with three frames. How many page faults would LRU and FIFO replacement algorithm?

(b) What are the disadvantages of single contiguous memory allocation? Explain.

Q-7.

(a) Briefly explain about single-level, two-level and three Structured directories.

(b) What is disk scheduling? Explain the C-SCAN scheduling by giving an example.

Q-8.

(a) Interrupt and spooling.

(b) UNIX file system.

(c) Program and system threats.