System element

A system element is the functionality supported by a device. For example, a server is a device. When this server runs a specific set of applications, it becomes a web server. The web server is the system element. The parent service component is a complete application system that depends on the web server (a system element) to make the actual service available to an end user.

  • Each service component contains zero or more system elements.
  • Each system element contains zero or more devices.
  • Each system element can support zero or more service components.

For example, an application server and web server are necessary to support an online book ordering system. A database is also essential to store customer and order information captured in the online book ordering system.

Example:

Store (category)

     Book Store (service definition)

          Buy new book (actual service)

                ...

          Buy used book (actual service)

                Orders application (service component)

                ...

                Catalog application (service component)

                    JBoss application server (system element)

                    IIS web server (system element)

               Shipment application (service component)

                ...

     CD Store (service definition)

          ...

 

In this example there are two system elements contained in the Catalog application. Each system element is defined by a record that is related to the subordinate device records.

Note This example also shows how a service component can also depend on an actual service (Database services) that has its own service component (a database application) and system elements (Oracle instances).

Book store system element diagram

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