What are different types of architectural styles?

Large number of computer systems are created. Some of the architectural styles are:

Data Centered Architecture
Data store resides at center of architecture and is accessed frequently by other components that update, add, delete or otherwise modify data within the store. A data centered architecture promotes integrability, which means existing components can be changed and new client components added to the architecture without concern about other clients.

Data-flow Architecture
Data flow architecture is applied when input data is to be transformed through a series of computational or manipulative components into output data. Pile and filter structure has a set of components called by filters connected by pipes that transmit data from one component to another. Each filter works independently. If data flow degenerates into a single line of transforms, it is called batch sequential.

Object Oriented Architecture
In this architecture, data and operations are encapsulated by the components of a system. Communication and coordination between components is done by message passing.

Call and Return Architecture
In this architecture, software designer achieves a program structure which is relatively easy to modify and scale. Two sub-styles exist: Main program/subprogram architecture and Remote Procedure Call Architecture.

Layered Architecture
In this architecture, different layers are defined. Each layer accomplishes operations that progressively become closer to machine instruction set. Components service user interface operations at outer layer. Components perform operating system interfacing at the inner layer.

What is an architectural style and pattern?

There are many architectural styles associated with the software that is built for computer based systems. The style describes a system category that encompasses:
- set of components.
- set of connectors enabling communication, coordination and cooperation among components.
- constraints.
- semantic models enabling a designer to understand overall properties of a system.

Architectural style is a transformation which is imposed on the design of an entire system. The intent is to establish a structure for all components of the system. When an existing architecture is re engineered, fundamental changes to the structure of the software results.
Architectural pattern imposes a transformation on the design of an architecture. Differences between pattern and style are:
- Scope of pattern is less broad.
- Pattern imposes a rule on architecture describing how software will handle some aspect of its functionality.
- Architectural patterns tend to address specific behavioral issues within context of architectural.
Patterns can be used in conjunction with an architectural style to establish the shape the overall structure of a system.