(Grid Index Information Service, a component of MDS) maintains a current index of all the registered resources known in the grid. It provides a means of knitting together arbitrary GRIS services to provide a coherent system image that can be explored or searched by grid applications. GIISes thus provide a mechanism for identifying "interesting" resources, where "interesting" can be defined arbitrarily. For example, a GIIS could list all of the computational resources available within a confederation of laboratories, or all of the distributed data storage systems owned by a particular agency. In Grid3 we are implementing a hierarchical GIIS structure. Read more at http://griddev.uchicago.edu/download/grid3/doc.pkg/GIIS- configuration/giis_config.doc .

Grid Index Information Service gathers information (using LDAP) from multiple GRIS servers and publishes static information about 'classes' of servers.