A philosophical and technical comparison of Legion and Globus

Grids are collections of interconnected resources harnessed to satisfy various needs of users. Legion and Globus are pioneering grid technologies. Several of the aims and goals of both projects are similar, yet their underlying architectures and philosophies differ substantially. The scope of both projects is the creation of worldwide grids; in that respect, they subsume several distributed systems technologies. However, Legion has been designed as a virtual operating system (OS) for distributed resources with OS-like support for current and expected future interactions among resources, whereas Globus has long been designed as a “sum of services” infrastructure, in which tools are developed independently in response to current needs of users. We compare and contrast Legion and Globus in terms of their underlying philosophy and the resulting architectures, and we discuss how these projects converge in the context of the new standards being formulated for grids.