CH 18 Distributed SE

Complexity (in distributed systems)

The increased design, implementation, and operational difficulty arising from coordinating many interacting components across a network.

Concurrency

The execution of multiple activities in parallel to improve responsiveness or throughput.

Distributed software engineering

The discipline of designing, building, and maintaining systems whose components run on different networked nodes.

Distributed system

A system where data processing is spread across multiple networked computers rather than confined to a single machine.

Fault tolerance

The ability of a system to continue providing service even when some components fail.

Inter-organizational computing

Distributed computing that spans multiple organizations, where nodes are controlled by different administrative domains.

Openness

A property where a system can interoperate with hardware and software from multiple vendors using agreed interfaces and standards.

Resource sharing

The ability of different parts of a distributed system to use common hardware or software resources.

Scalability

The capability of a system to handle increased load by adding more resources, such as servers or processors.

Client-server architecture

An arrangement where servers provide services and clients request them, typically across a network.

Embedded system

Software running on a dedicated processor or small set of processors within a larger device or product.

Fat client

A client that runs most application logic locally, leaving data management largely to the server.

Multiprocessor architecture

A design where multiple processes run on one or more processors, often used in real-time or safety-critical systems, sometimes under dispatcher control.

Personal system

A non-distributed system intended to run on a single personal computer or workstation.

Thin client

A client that mostly handles presentation, relying on the server for application logic and data management.

Three-tier architecture

A client-server variant where presentation, application logic, and data management are each placed on separate logical or physical tiers.

CORBA (Common Object Request Broker Architecture)

An international standard that specifies an ORB, object model, services, and components so distributed objects can interoperate across languages and platforms.

CORBA services

A set of standard services—such as naming, notifications, and transactions—intended to support many kinds of distributed applications.

Distributed object architecture

A style where every distributable unit is an object that can both consume and offer services to other objects.

IDL (Interface Definition Language)

A language-neutral way of describing object interfaces so they can be mapped to various programming languages.

Middleware

Software that sits between application components and the network, managing communication, coordination, and sometimes additional services.

Object Request Broker (ORB)

Middleware that routes requests between distributed objects, using interface definitions to invoke the correct operations.

Decentralized P2P architecture

A P2P network structure where there is no central coordinating node; peers communicate directly.

Peer-to-peer (P2P) architecture

A decentralized architecture where each node can act as both client and server, contributing processing and storage.

Semi-centralized P2P architecture

A P2P structure where some central nodes play a coordinating or indexing role while peers still share resources.

Provider independence

The ability to use services from different providers without changing the client's core logic.

Service composition

The practice of building new functionality by wiring together existing services, often at runtime.

Service-oriented architecture (SOA)

An approach where applications are built by composing reusable, externally provided services accessed over standard web protocols.

SOAP (Simple Object Access Protocol)

An XML-based protocol for exchanging structured messages between web services.

UDDI (Universal Description, Discovery and Integration)

A standard mechanism for publishing and discovering web services in registries.

Web service

A reusable software component accessible over the web using standardized interfaces and message formats.

WSDL (Web Services Description Language)

An XML-based language for describing the operations, parameters, and bindings of a web service.

ATM client-server system

A banking application where ATMs act as clients and backend systems provide services such as account queries and updates.

Data mining system

A distributed object system that accesses multiple databases and uses integrator objects to discover new relationships.

In-car information system

A service-based automotive system that uses GPS to access remote services for traffic, weather, and local information, delivering results through the car radio.