This set of use cases was contributed to XSEDE by the ATLAS project: one of several scientific teams working with experimental data generated by the Large Hadron Collider (LHC) at CERN. The use cases were heavily influenced by Open Science Grid (OSG) architectural concepts. These combined use cases were a proposal for how to make XSEDE resources behave similarly to OSG's Compute Elements (CEs) and Storage Elements (SEs), and thus add XSEDE resources to the set of services available to OSG Virtual Organizations (VOs). The XSEDE-1 Architecture & Design team felt that these use cases, as currently written, were too closely tied to the one-of-a-kind LHC instrument, and too prescriptive of a specific implementation to be useful in the XSEDE foundational architecture. Though they are not recognized as a well-understood way to use the XSEDE system, they may serve both as a basis for understanding what OSG-based projects expect from a system and as a starting point for documenting how XSEDE can be used by projects that already use OSG. The Federation & Interoperation use cases, which are accepted as well-understood XSEDE use patterns, resulted from generalizing these OSG/LHC-specific use cases.