We reached the end of the UML diagrams. Now it's perfect time to look at the hardware. As you can see, we moved from items that live in analysis, to components that live in computers, to hardware that lives in the real world.
Hardware, of course, is a prime topic in a multicomponent system. A solid blueprint for hardware deployment is essential to system design. The UML provides you with symbols for creating a clear picture of how the final hardware setup should look.
The main hardware item is a node, a generic name for any kind of computing resource. Two types of nodes are possible. A processor is a node that can execute a component, and a device that can't execute a component. A device typically interfaces in some way with the outside world.
In
the UML a cube represent a node. Node has its name, and you can use a stereotype to
indicate the type of resource it is. If a node is a part of package, then and the name of
package preceeds the name of the node. A line joining the two cubes represents a
connection between two nodes. You can use a stereotype to provide information about the
connection.
The cube is representation of a node in the UML |
Also every node deployes some of software components in the system. To indicate deployed components, you show them in dependency relationships with a node.
Let's build a
deployment diagram for a home computer system. Computer consists of these hardware
elements: CPU, monitor, printer, mouse, keyboard. And installed software components:
Windows98, Office98, InternetExplorer4, FrontPage, DOS, NortonCommander, TurboPascal.
The main node is CPU which consists of all the software components with their relationships. Other hardware elements are devices connected to the main processor unit. |
You may extend this diagram by adding a modem and connection to the Internet. Try to redraw the diagram with this extension.
The
UML deployment diagram provides a picture of how the physical system will look when it's
all put together. A system consists of nodes (represented by a cube) with line connecting
them, called connections. There are two types of nodes: a processor (can execute a
component) and a device (interface with the real world). Deployment diagrams are useful
for modeling networks.