In this work, we demonstrate the power of providing a common set of operating system services to Grid Architectures, including high-performance I/O, communication, resource management, and process management. In the last few years, a number of exciting projects like Globus, Legion, and UNICORE developed the software infrastructure needed for grid computing. However, operating system support for grid computing is minimal or non-existent. Tool writers are forced to re-invent the wheel by implementing from scratch. This is error prone and often results in sub-optimal solutions. To address these problems, we are developing GridOS, a set of operating system services that facilitate grid computing. The services are designed to make writing middleware easier and make a normal commodity operating system like Linux highly suitable for grid computing. The modules are designed to be policy neutral, exploit commonality in various grid infrastructures and provide high-performance. Experiments with GridOS verify that there is dramatic improvement in performance when compared to the existing grid file transfer protocols like GridFTP. Our proof-of-concept middleware shows that writing middleware is easy using GridOS.