37.1. Deployment Diagrams
A deployment diagram shows the assignment of concrete software artifacts (such as executable files) to computational nodes (something with processing services). It shows the deployment of software elements to the physical architecture and the communication (usually on a network) between physical elements. See 656.
Figure 37.1. A deployment diagram.
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- device node (or device )
A physical (e.g., digital electronic) computing resource with processing and memory services to execute software, such as a typical computer or a mobile phone. - execution environment node (EEN)
This is a software computing resource that runs within an outer node (such as a computer) and which itself provides a service to host and execute other executable software elements. For example:- an operating system (OS) is software that hosts and executes programs
- a virtual machine (VM, such as the Java or .NET VM) hosts and executes programs
- a database engine (such as PostgreSQL) receives SQL program requests and executes them, and hosts/executes internal stored procedures (written in Java or a proprietary language)
- a Web browser hosts and executes JavaScript, Java applets, Flash, and other executable technologies
- a workflow engine
- a servlet container or EJB container
As the UML specification suggests, many node types may show stereotypes, such as «server», «OS», «database», or «browser», but these are not official predefined UML stereotypes.Note that a device node or EEN may contain another EEN. For example, a virtual machine within an OS within a computer.A particular EEN can be implied, or not shown, or indicated informally with a UML property string; for example, {OS=Linux}. For example, there may not be value in showing the OS EEN as an explicit node. instances are shown with an underline under their name, and the absence of an underline signifies a class rather than an instance. Note that a major exception to this rule is instances in interaction diagramsthere, the names of things signifying instances in lifeline boxes are not underlined.