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Report(1)+CM(1)
Report(1)+CM(2)
Report(1)+CM(military,1)
Report(1)+CM(3)
Report(1)+CM(military,2)
and so on ...
and so on ...
Figure 3-13: Successors and Variants
The picture given in Figure 3-13 describes the structure of a collection of versions of a
single transfer item. A similar sort of picture can be drawn for a collection of versions of a
configuration item. The tree structure shown in Figure 3-13 applies equally well to configuration items.
ISTAR recognizes two symbolic successor numbers. They are #L, meaning latest or last
successor, and #P, meaning preferred successor. These symbolic numbers are of use
when a transfer item is imported into a tool’s work area. Thus the name
Report(#P)+CM(#L)
in an import operation calls for the preferred version of the report as a whole (the configuration item) and, within that, the latest version of the configuration management section. The identity of the preferred version of an item is set within the component management tool (CMT).
Although the application of successor numbers and variant names is the same for configuration and transfer items, the operations which create the successors and variants
differ for the two classes of items.
As noted, transfer items are transferred between work areas and contract databases.
Therefore, it is the export operation, which moves the item from the work area to the
database, which creates successors and variants of transfer items. Many of the
workbenches have specialized export operations for new, successor, and variant transfers. In many cases, the VALIDSET key (described in an earlier section) will provide a list of
transfer items in the contract for which the tool may export successors or variants. In all
cases, the user must give the full name, in the ‘‘ciname+xiname’’ format displayed earlier,
of the item being exported.
CMU/SEI-88-TR-3
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