Abstract: The representation, description, organization, deployment, discovery, access, maintenance and final destroy of resources are important research problems in grid computing, as they directly affect the design and implementation of grid protocols, grid languages, and grid software. In this paper, a grid is viewed as a virtual computer, and these problems are studied from a computer architecture viewpoint, using the methodology accumulated in past address space studies. A formal model of grid resource space with three layers is proposed: effective resource space, virtual resource space, and physical resource space, and thus it is called the EVP model. This model is used in the design and implementation of the GSML software suite and the grid operating system of the Vega grid project. This three-layer approach could enhance the usability, modularity, transparency, and autonomy of grid systems. This EVP model could be used not only for computing grid, but also for data grid, information grid, business grid, and peer-to-peer systems.