Three-tiers For Client-Server!!!
Three tier systems benefit everyone in the organization, especially people in IT departments. The three-tier model is appealing for enterprise-wide distributed transaction-processing applications in that it offers these advantages:
- Centralization permits IT to control and secure programs and servers using an already-accepted, mainframe-like environment that''s scalable, predictable, and easily monitored.
- Reliability is enhanced since equipment resides in a controlled environment that can be easily replicated or moved onto fault-tolerant systems.
- Scalability is easier since servers or processors can be added to achieve acceptable levels of performance. Centralized database services tend to be more optimal since constant monitoring leads to prevention and quick detection of server or network problems.
- Flexible, well-defined software layers permit the highest degrees of IT responsiveness to changing business needs. With lightweight and inexpensive client desktop requirements, wholesale changes to desktop systems can be made at any time without any effect on the program layer or the database layer, allowing companies to quickly adopt improvements in technology. Additionally, non-PC clients (e.g. POS devices, voice-response units, handheld devices, etc.) can be used at any time since the interfaces to the application are based on open industry standards and are well-defined to the developer.
- Existing mainframe services can be reused through the virtue of a flexible data layer. Mainframe services can be made to look just like any other data service layer, thus preserving the transaction processing capabilities of mainframe. This is significant since mainframes tend to be optimal environments for high-volume transaction processing.
- Systems based on open industry standards allow companies to rapidly incorporate new technologies into the operation without concern of inter-operability problems that exist in products based on proprietary approaches.
