Grid computing allows for sharing and coordinated use of diverse computing resources virtually. It provides uniform access to computational resources over the Internet similar to how the web provides access to documents. Key motivations for grid computing include enabling large-scale science through geographically dispersed resources. Grid architectures have fabric, connectivity, resource, collective, and application layers. The Globus Toolkit is commonly used open source software that provides components for security, data management, scheduling, and more. Grids are used in various domains like earthquake and climate simulation.