The following explanation is based on November Rosario CTP, and it is only my understanding of the product. Maybe I haven't got it right. Comments are welcome.
When you look at Rosario's CMMI work items, you meet some old and new types which used for Requirement Management:
- Business objective (new)
- Feature (new)
Now, as far as I could see, the CMMI project site hasn't been updated yet with descriptions for the new work item types, so I will try to describe their roles by myself.
A little bit about Relations
Rosario presents different types of relations between work items.
Parent - Child
Fulfilled by - Fulfills
Predecessor - Successor
Tested by - Tests
Related - Related
Some work items defines what type of relation they should be part of.
See below for details.
As I understand, it should represent a objective which can be achieved in multiple ways. it doesn't come to describe what should be done, it comes to describe what should be achieved.
It's possible to have a tree of BO (Business Objective), but it seems Microsoft doesn't mean you use it in that way (you can see it by the lack of "parent-Child" in its UI).
Its main use is with Feature in "Fulfilled by - Fulfills" relation.
Feature, in contrast with BO, describe what should be done, in different levels of abstraction.
This work item suggested to be used in tree like "Parent-child" Hierarchy of Features. It can also take part in relation of "Fulfilled by - Fulfills" with Business Objectives.
Features and Requirement are really similar, and the only difference I could point out is that while Feature has the "Fulfilling" connection to other items (probably for use with BO) Requirement doesn't. in fact, it doesn't have a built in UI for a "Parent-Child" relation either, so it seems Microsoft wants us to use it as the most detailed and low level item in "Requirement Management" before Task level.
to be continued...