1. A method by which a client connected to a data repository over a lower speed network connection may provide higher speed access to a data item for application processing by an application server than is possible over the relatively low speed connection to the network, the method comprising: determining a digital fingerprint of the data item; testing for whether the data item is already stored in the repository by comparing the digital fingerprint of the data item to digital fingerprints of data items already in the repository; if the data item is not already stored in the repository, transferring the data item over the lower speed connection from the client to the repository; assigning an expiration time to the data item, before which time both modification and deletion are prohibited; making a higher speed connection between the application server and the data repository; executing an application on the application server to process the data item stored in the data repository; and returning a result of the executing step to the client across the lower speed connection; wherein the client has a plurality of data items stored in the data repository and the client controls which of the plurality of data items the application server is allowed to access; wherein the plurality of data items are archival records of data that were persistently stored in non-volatile storage outside of the repository; wherein, after the expiration time is assigned and before the expiration time has passed, the client can change the expiration time to a later time but no action taken by the client can cause the expiration time to be changed to an earlier time or cause the data item to be deleted; and wherein after the expiration time has passed deletion of the data item is allowed.