Introduction to Distributed Systems

Form of Internet-based computing, whereby shared resources, software and information are provided to computers and other devices.

Distributed systems have become a cornerstone of modern computing environments, powering everything from the internet to cloud computing. This unit provides an introduction to distributed systems, exploring their principles and the challenges they present.

Definition of Distributed Systems

A distributed system is a collection of independent computers that appears to its users as a single coherent system. In other words, a distributed system is one in which components located on networked computers communicate and coordinate their actions only by passing messages. The computers that are in a distributed system can be physically close together and connected by a local network, or they can be geographically distant and connected by a wide area network.

Importance and Applications of Distributed Systems

Distributed systems are crucial in today's digital age because they allow us to achieve a level of computing power and functionality that would not be possible with a single system. They are used in a wide range of applications, including:

• Internet Services: Websites, email, online gaming, and social networks all rely on distributed systems.
• Telecommunications Networks: Mobile networks, telephone networks, and the internet itself are all examples of distributed systems.
• Scientific Computing: Distributed systems are used to process large amounts of data in fields like genomics, meteorology, and physics.
• Financial Services: Banks and other financial institutions use distributed systems for transactions, fraud detection, and risk analysis.

Principles of Distributed Systems

The design and operation of distributed systems are guided by several key principles:

• Transparency: This principle states that the distributed nature of the system should be invisible to the user. The user should interact with the system as if it were a single entity, not a collection of independent components.
• Scalability: Distributed systems should be able to accommodate growth in users and resources without suffering a loss in performance.
• Reliability: Distributed systems should be reliable, meaning they should continue to function correctly even when individual components fail.
• Performance: Distributed systems should provide a high level of performance, efficiently utilizing the resources they have available.

Challenges in Distributed Systems

Despite their many advantages, distributed systems also present several challenges:

• Communication: In a distributed system, components communicate by passing messages over a network, which can be slow and unreliable.
• Concurrency: Multiple components in a distributed system often need to perform tasks simultaneously, which can lead to conflicts.
• Failure Handling: Components in a distributed system can fail independently, making it difficult to ensure the overall reliability of the system.
• Security: Distributed systems are often more vulnerable to security threats than single-system architectures.

In the next units, we will delve deeper into these challenges and explore strategies for overcoming them, focusing particularly on the concept of system availability.