SirsiDynix: Technology: Client/Server Architecture

n-Tier Client/Server Architecture

n-Tier Client/Server Architecture

The SirsiDynix Unicorn® Library Management System features an elegant design that employs an n-tier client/server architecture, the flexibility of which enables scalability and modularity. Such architecture is essential to relieve the pressure of expanding networks on network servers and to provide a method of protecting the integrity of user records. The Unicorn system is carefully partitioned to provide an advanced architectural approach in which the functionality of the application is spread across multiple tiers: data management, applications logic, and presentation. Data management and applications logic exist on the server, while client software performs applications logic and all presentation functions.

The SirsiDynix WorkFlows® staff client software sends transaction requests to a system agent, which verifies and routes the requests to a transaction processor program on the server. The transaction processor program returns responses through the agent to the originating client. This economical multi-tiered architecture enables libraries to scale Unicorn to a size that best meets their needs. For example, a library with high circulation can meet its continuous demand for check-in/check-out transactions by activating multiple instances of the circulation transaction processor program. If the first program is engaged, the agent immediately routes the client's request to an alternate transaction processor program.

Unicorn also enables libraries to scale their system in response to changing needs. Special monitoring programs report the amount of traffic presented to Unicorn's transaction processor programs and the number of times, if any, a wait-state was encountered by an incoming transaction. After reviewing the logs of this monitoring program, the library can adjust its system configuration by activating additional instances of high-demand transaction processor programs, easily and dynamically tuning its system to meet its unique operational needs.

Unicorn meets the needs of libraries around the globe. Incorporation of the Unicode standard offers libraries significant cost savings over the use of legacy character sets. Unicorn also provides this internationalization on the client side: because the client handles all presentation features, language support is offered for multiple languages for both staff and users.