Q1. What is a Distributed System and what is the need for it? Explain properly?

Ans1. A distributed system is a network of interconnected computers or nodes that work together to achieve a common goal, even though they are physically separate and may be located in different geographic locations. In a distributed system, these nodes communicate and coordinate their actions to provide a unified service to the end-users or applications.

Diagram:

Need for Distributed Systems:

Scalability: Distributed systems can handle growing workloads and accommodate more users by adding additional nodes or resources. This is essential for web applications and services that experience fluctuating demand.

Reliability: By distributing data and processing across multiple nodes, distributed systems can provide redundancy and fault tolerance. If one node fails, the system can continue to operate, ensuring reliability.

Performance: Distributed systems can improve performance by distributing tasks among nodes, reducing the workload on individual machines. This is crucial for applications that require high performance and low latency.

Resource Sharing: Distributed systems enable efficient resource sharing, such as distributed file storage, distributed databases, and distributed computing clusters. This optimizes resource utilization.

Fault Tolerance: Distributed systems are designed to be fault-tolerant. If one node fails, others can take over the tasks, ensuring uninterrupted service.

Cost-Effective: Distributed systems often use commodity hardware and open-source software, making them cost-effective compared to scaling up a single monolithic system.

Q2. What is idempotency? How does a duplicate request is handled in two message IPC protocol for client-server communication?

Ans2. Idempotency is a concept in computer science and networking that means a specific operation or action can be performed multiple times, and the end result will be the same as if it were performed only once. In other words, regardless of how many times you execute an idempotent operation, the system's state or data will not change beyond the initial operation.

In the context of two-message IPC (Inter-Process Communication) protocols for client-server communication, handling duplicate requests can be challenging. In such protocols, a client sends a request message to the server, and the server processes the request and sends a response message back to the client

Duplicate Request Handling:

Even with idempotent requests, it's possible for duplicates to occur due to network issues or client retries. To handle duplicates, servers often use a combination of techniques:

Request Deduplication: Servers may maintain a record of recently processed requests and their outcomes. When a duplicate request is received, the server checks its records to determine if the request has already been processed. If it has, the server can respond with the previous result.

Idempotent Request Handling: The server ensures that idempotent requests are processed consistently, regardless of duplication. For non-idempotent requests, servers may need to keep track of previously processed non-idempotent requests to avoid unintended side effects.

Response Caching: Servers may also cache responses for a certain duration. When a duplicate request is received, the server can return the cached response to the client without reprocessing the request.

It's essential to handle duplicate requests carefully to avoid unnecessary resource utilization and ensure that the system remains consistent and predictable.

Q3. A client makes remote procedure calls to a server. The client takes 5 milliseconds to compute the arguments for each request, and the server takes 10 milliseconds to process each request. The local operating system processing time for each send or receive operation is 0.5 milliseconds, and the network time to transmit each request or reply message is 3 milliseconds. Marshalling or unmarshalling takes 0.5 milliseconds per message.