The Advanced Resource Connector (ARC) middleware integrates computing resources (usually, computing clusters managed by a batch system or standalone workstations) and storage facilities, making them available via a secure common Grid layer.

The Virtual Data Toolkit (VDT) is an ensemble of distributed computing software that can be easily installed and configured. The goal is to make it as easy as possible for users to deploy, maintain and use distributed computing software. The VDT is a product of the Open Science Grid (OSG), which uses the VDT as its software distribution.

The Globus Toolkit is a fundamental enabling technology for building grids that allow distributed computing power, storage resources, scientific instruments, and other tools to be shared securely across corporate, institutional, and geographic boundaries.

EMI is a collaboration of the three major middleware providers in Europe, ARC, gLite and UNICORE, and other consortia. It aims to deliver a consolidated set of middleware components for deployment in EGI, PRACE and other DCIs; extend the interoperability between grids and other computing infrastructures; strengthen the reliability of the services; and establish a sustainable model to maintain and evolve the middleware, fulfilling the requirements of the user communities.