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Middleware for Smart Environments [jCook:05][on going]

Smart Environment Components:

• Sensor Hardware
• Sensor Software
  • Both help in perceiving/sensing the environment
• Application Software
  • Interprets and reasons about the perceived data
• Effector Control Software
  • Act on the environment
• Some Support Systems

Smart Environment Implementation Layers:

• Hardware layer
• Operating System Layer
• Middleware Layer
• Application Software Layer

Middleware Layer:

Acts between Operating System layer and Application software layer. Lies between the software applications it assists and the platform it is based on.

Middleware layer provides supports like:

• Facilitate Rapid Development
• Easy of Integration
• Improved Reliability
• Increased Scalabilit
• Transparency
• Interoperability

Some Points

• These supports/services will help smart environment possible.
• These middleware services may be implemented as part of the Operating System
• Some middleware services may be implemented as part of the Application Softwares themselves
• But to make the smart environment practical a separate and generalized middleware layer providing the above services is more desireable that can enhance rapid and easy smart application development using these service components.
• Middleware can be a single layer above operating system or can be an additional layer on an existing middleware layer. Purpose is providing more abstractions to the applications.
• Middleware framework is another concept that can combine more than one middleware components and services to provide additional services or to provide interoperability among those middlewares
• From the developers viewpoint: Middleware will provide some API to be used by application developers. Also a middleware will have some protocols (rules and components supported)

Evolution of Middleware:

Middleware is mostly about communication.

Step 1: using of punch card programming: using punch cards/even flipping switches for programming

Step 2: Using of MainFrame Computer: Computing done in a central place. Users interact through terminals

Step 3: File sharing architecture: With the invent of PCs File sharing architecture evolved. PCs download files from shared locations, perform jobs and submit to the shared locations. Over time the PC LAN became over crowded for this paradigm.

Step 4: Client-server architecture evolved. File servers were replaced by database servers who respond to users requests and supply only the required data rather than total file. Network load decreased

1. Two Tier
2. Three Tier

Two Tier: Client layer(Sytem Interface) and a Server layer (DBMS). An additional component that is shared by the two layers mainly for process management:initiation, conduct and publish of the results. Resource management, adjust to client's capability.

Three Tier: The shared component in the two tier architecture is given the form of a 3rd layer in between client and server layers. This additional layer takes care of

• Process Management by providing logic and rules to control job processing
• Queueing of messages

This additional layer helps in

• increasing the number of clients it can handle
• increased performance
• system's flexibility improvement
• maintainability, reusability, scalability

This architecture has become the basis for many middleware solutions. We can think the additional layer in between client and server layer as the middleware layer.

Middleware Framework:

Middleware Frameworks usually target at some specific application domains. They consist of software environments that provide

• An API
• A User Interface
• Tools for application development
• Tools for System Management

Frameworks can provide their own private middlewares. Frameworks can also utilize other commonly available middleware services for that application domain. For a specific domain, a framework usually provides better solutions than general middlewares as they are especially designed for that domain. It is usuaaly easier for the developers to use frameworks for application development and testing. Frameworks can also be called middlewares themselves because they provide the same/similar purpose. Many middlewares do not have any visible part but frameworks usually have visible parts.