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VERS STORY | STANDARD | ASSESSMENT | PROJECTS | DIGITAL ARCHIVE | TRAINING | TOOLKIT | PUBLICATIONS | |
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2.1 Self-sufficiency To minimise the possibility of losing a record it is necessary to minimise the dependency of the record on systems, other data, or documentation. The ideal record is self-sufficient. The rationale behind this principle is simple. Increased dependency increases the points of possible failure. If access to a record is dependent on a system, for example, then the loss of that system means the loss of the record. The most critical dependency with an electronic record is the dependency on the application that interprets a digital object and renders the contents. If the application is lost, typically because it will no longer run on existing computer systems, the records can no longer be displayed and consequently are lost. For this reason VERS requires content to be migrated to a standard long-term preservation format. Ultimately, the worst-case scenario is that it becomes necessary in the future to implement new software to render record content. In this scenario, the VEO must contain enough information to allow the format of the content to be identified and sufficient details of the format obtained to allow re-implementation. No record can be completely self-sufficient because that would require the storage of all the supporting documentation for the long-term preservation format with the record itself. However, if a specification or standard is sufficiently widely published that a copy can reasonably be expected to be found in a public library (or the electronic equivalent) for the foreseeable future, it is sufficient to reference the specification or standard in the record. This issue is discussed further in the advice on PROS 99/007 Specification 4: VERS Long Term Preservation Formats (Advice 13). Electronic records may have other dependencies which may be less obvious. For example, a 'large' collection of records requires some means to allow users to find the records they are interested in. One method is to provide an index. But what happens if this index is lost? The records may still exist, but if it is not possible to recreate the index the contents may be inaccessible. Self-sufficiency requires that a record include a copy of its indexing information. If the external index is destroyed it should be able to be rebuilt using the information stored in the records themselves. In summary, a good design for an archivable record is record-centric. It minimises the dependency of the record on systems, outside data, and documentation. However, very well-known information can be included by reference to reduce overhead. | |||||
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