The MSC Editor You turn to the MSC editor to diagram each use case, which is like the script of a play. You ca n read use-case diagrams to determine the actions that unfold as the system operates. Other methodologies call use cases usage scenarios or event traces . Thus, a scenario might be shown as a block labeled SCSI read in an MSC diagram, while the MSC would be the chart detailing the steps of the read operation. It's important to note that the charts you build with the MSC editor show discrete activities, so you cannot use it to model the entire behavior of the system.
Use cases are helpful in determining derived requirements of objects.
In other words, working out the use case for a particular event may reveal an attribute that was omitted from an object participating in that event. It's a two-step process. The hierarchy editor is similar to one found in the MSC editor and is likewise a means of grouping similar activities. With the interconnection editor, you can model communication between objects in the system like in a wiring diagram. It's easy to get confused here, because you're likely to conclude that objects in the SDL editor are the same as those you built in the OMT editor.