... Each installation operates local hardware and a locally configured software release. ... The archive serves both as a storage area for existing data and as an active data store interacting with daily Chandra X-ray Center (CXC) operations. ... Data are entered in the archive at a primary installation and are replicated to secondary installations. ... All data are stored at their primary installation where they are ingested in the archive by data production operations. ... Patz et al 2003, in ASP Conf...