| An ever increasing amount of information is being stored digitally, and people are becoming more and more dependent on it. However, very little is understood about how to preserve digital information for long time periods. Media failures, natural disasters and bankruptcy all conspire to cause information loss over decades or centuries. Such failures rob future generations of vital scientific and cultural artifacts.; To address this problem, we have developed a distributed digital archive that is based on the concept of multiple autonomous archives cooperating to provide preservation. For such a system to effectively preserve data for the long term, it must be as self-supervising as possible. Moreover, the system should be structured so that autonomous archives have an incentive to collaborate and share resources. This dissertation discusses the design and implementation of a distributed archive that has these properties. At each archive site, an import module automatically transfers important digital information into a write-once archive store. This information is then replicated to remote sites through a data trading negotiation, which ensures that the information is preserved even in the case of whole site failures. A robust and scalable searching mechanism allows users to locate data anywhere in the archive network, even if the original index or search portal has failed. |
