Question

Explain why the use of distributed objects with an object request broker simplifies the implementation of scalable client-server systems. Illustrate your answer with an example.

Short answer

Distributed objects with an ORB simplify scalable systems by abstracting communication and allowing seamless component integration.

Step-by-step solution

Understanding Distributed Objects

Distributed objects allow components in a system to run on different networked computers while appearing as if they were a part of a single system. This abstraction simplifies development as it allows developers to write code as if all components reside in the same application rather than worrying about the details of communication.

Role of Object Request Broker (ORB)

An ORB facilitates communication between distributed objects, taking care of message passing, locating objects on the network, and ensuring that requests are appropriately handled. This means developers don't need to implement the network communication code themselves, which simplifies the system's architecture.

Simplified Scalability

The use of an ORB and distributed objects allows developers to scale a system more easily by adding more servers or distributed components without needing substantial changes to the application logic. The ORB manages object references and communication, allowing new servers to be added seamlessly.

Example Illustration

Consider a banking system where different services like authentication, account management, and transactions are spread across multiple servers. Without an ORB, developers would need to handle server-specific communication for these services. With an ORB, each service is simply a distributed object, and the ORB manages communication, allowing easy integration and scalability.

Key concepts

Object Request Broker (ORB)

The Object Request Broker (ORB) is a middleware technology that simplifies communication in distributed systems by acting as a conduit for messages between distributed objects. In simpler terms, an ORB handles the complex networking tasks associated with communicating across diverse environments. This includes message passing, object location, and request management, which significantly streamlines the development of distributed systems.

By using an ORB, developers can focus on the business logic of their applications without delving into the complexities of network programming. It essentially hides the details of inter-component communication, enabling modules to interact as though they are part of a single application on the same machine. This increases productivity as developers do not need to implement the low-level networking code required to ensure components can effectively communicate and work together. Moreover, ORBs often provide additional services such as lifecycle management, security, and transaction management, thus contributing further to simplified and efficient system development.

Scalable Client-Server Systems

Scalable client-server systems are designed to handle increasing amounts of work or users without losing performance. Distributed objects, combined with an ORB, simplify the creation of scalable client-server architectures. This is because such systems can grow organically by adding more servers or components without requiring extensive changes to the existing code base.

This inherent scalability is achieved through the ORB's ability to manage distributed object references and ensure communication between them is seamless regardless of their deployment across multiple servers. As the load on the system grows, developers can simply deploy additional instances of the necessary components. The ORB ensures they integrate smoothly into the existing architecture, maintaining operational consistency and efficiency.

In essence, scalability is manifested through the decoupling of components, allowing each to be updated or scaled independently. Hence, for a client-server system, adding processing power and redundancy becomes a routine task rather than a major overhaul. The ORB provides the necessary tools to abstract these complexities away from the developers, allowing them to focus more on enhancing and extending the application functionality.

System Architecture

System architecture refers to the structured design and organization of a system's components and their interactions. In distributed systems, an effective architecture incorporates flexibility, scalability, and robustness, easily achieved with distributed objects and an ORB. This architecture separates system functionalities into distinct modules or objects that can reside on various networked computers.

The inclusion of an ORB in the architecture allows for a more efficient system design where components are loosely coupled. This modular approach ensures that any changes or updates to one component do not adversely affect others, simplifying maintenance and updates.

Furthermore, the system architecture benefits from the ORB by enabling transparent communication across components. This means that regardless of where a component physically exists, it can interact with other parts of the system as if they are all co-located. Such an architecture not only simplifies development and deployment but also enhances system performance and reliability by mitigating points of failure and bottlenecks through distributed processing.

Networked Computers

Networked computers form the backbone of distributed systems, enabling components to communicate and work collectively as a cohesive unit. With distributed objects, individual modules of a system are deployed across various networked computers, each leveraging the computational power and resources of its host.

The beauty of utilizing networked computers in a distributed system lies in their ability to share the computational load. This means a task can be distributed across multiple machines, therefore increasing the system's overall processing power and efficiency. An ORB further augments this by managing the communication across these computers, ensuring a smooth flow of information and coordination between distributed objects.

This network of interconnected computers allows for great flexibility and resilience. If one computer fails, the system can still continue to function, as other nodes can take over the failed system’s role. Additionally, geographically dispersed computing resources can be harnessed together, providing optimal performance regardless of user location, and offering a scalable solution that can be expanded or modified as the demands on the system change.