Type of subsystems for concurrent, real-time, or distributed application domains
- <<Server>>
A server subsystem provides a service for other subsystems. In the simplest case, a server object could consist of a single entity object.
- <<User interface>>
A user interface subsystem provides the user interface and acts as a client. There may be more than one user interface subsystems. A user interface subsystem is usually a composite object that is composed of several simpler user interface objects.
- <<I/O subsystem>>
In some systems, grouping al the device interface classes into an I/O subsystem might be useful, because developing device interface classes is a specialized skill.
- <<System services>>
Certain services are not problem domain-specific but provide system-level services, such as file management and network communication management.