The user copies a request file from his own network node to his CDDS account, and the ensuing transfers are effected using FTP-based protocols. This service is wholly controlled by ESOC and does not require any input from external users. The latter are then packaged and shipped to authorised members of the Cluster scientific community around the world. The set of CD-ROMs for any given day must be delivered to the scientific community within three weeks of the data's generation. A format compliant with the ISO 9660 level 1 standard is used for the CD-ROMs, so that the disks are readable on all common platforms, e.g. UNIX, VMS, PC and Macintosh.
Software licences are also usually cheaper for small computers.
Furthermore, the distributed architecture allows the optimum use of licences across the system. In the distributed architecture, each element is independent, and failure of one does not generally affect the others. Furthermore, the global system performance is not compromised by heavy resource usage by one element. In the distributed architecture, off-line tasks are hosted on a dedicated computer. The experience gained in the Cluster preparation activities has shown that this distributed architecture for science operations provides greater flexibility and allows trade-offs to be made between the various elements of the overall system.