In UCM Clearcase :
a component can be built into a functional unit of software. Multiple projects can use the same component. For the project responsible for maintaining the component, the project manager makes the component modifiable. For projects that may use that component to build other components.
A baseline identifies one version of every element visible in a component. In effect, a baseline is a version of a component. Baseline definitions are stored in project VOBs (PVOBs).
