APPLICATION SERVER

An application server is a type of server designed to install, operate and host applications and associated services for end users, IT services and organizations. It facilitates the hosting and delivery of high-end consumer or business applications, which are used by multiple and simultaneously connected local or remote users.

An application server consists of a server operating system (OS) and server hardware that work together to provide computing-intensive operations and services to the residing application. An application server executes and provides user and/or other app access when utilizing the installed application's business/functional logic. 

Key required features of an application server includes:

•  data redundancy

•  high availability

•  load balancing

•  user management

•  data/application security and 

• a centralized management interface.

 Moreover, an application server may be connected by enterprise systems, networks or intranet and remotely accessed via the Internet.

 The application server is frequently viewed as part of a three-tier application, consisting of a graphical user interface (GUI) server, an application (business logic) server, and a database and transaction server. More descriptively, it can be viewed as dividing an application into:

• A Presentation-tier, front-end, Web browser-based graphical user interface, usually at a personal computer or workstation

• A middle-tier or application tierl business logic application or set of applications, possibly on a local area network or intranet server.

• The third-tier or data tier, back-end, database and transaction server, sometimes on a mainframe or large server

Older, legacy application databases and transaction management applications are part of the back end or third tier. The application server is the middleman between browser-based front-ends and back-end databases and legacy systems.