Hi Andrew, Mark, and Steve, OGSA-Data WG has a suggested service level terms (they call policies) in their OGSA data architecture document. - Throughput: the number of access requests that can be satisfied per unit time. - Response time: the time allowed to satisfy an access request. - Availability: the percentage of time that the service must be up. - Recovery time: time allowed for the service to recover from a failure. - Data resiliency: a specification of the effort the service should make to ensure that data is not lost in the face of failures. - Access accuracy: if the primary source of some data is not available, how should the service act? Report an error? Find an alternate source (with potentially stale data)? Return partial answers? Another term for this policy might be degradation of answers. - Currency of data: can the data used by the service, and the data returned, be out of date? If so, by how much? I've put them on GridForge SLT design team wiki page for future reference. Thanks, -- Hiro Kishimoto