The repository shall have a description of how AIPs are constructed from SIPs

This is necessary in order to ensure that the AIP(s) adequately represents the information in the SIP(s).

Process description documents; documentation of the SIP-AIP relationship; clear documentation of how AIPs are derived from SIPs.

In some cases, the AIP and SIP will be almost identical apart from packaging and location, and the repository need only state this. In other cases, complex transformations (e.g., data normalization) may be applied to objects during the ingest process, and a precise description of these actions may be necessary to reflect how the AIP(s) has been adequately transformed from the information in the SIP(s). The AIP construction description should include documentation that gives a detailed description of the ingest process for each SIP to AIP transformation, typically consisting of an overview of general processing being applied to all such transformations, augmented with description of different classes of such processing and, when applicable, with special transformations that were needed. Some repositories may need to produce these complex descriptions case by case. Under such circumstances case diaries or logs of actions taken to produce each AIP should be created and maintained. In these cases, documentation should be mapped to individual AIPs, and the mapping should be available for examination. Other repositories that can run a more production-line approach may have a description for how each class of incoming objects is transformed to produce the AIP. It must be clear which definition applies to which AIP. If, to take a simple example, two separate processes each produce a TIFF file, it must be clear which process was applied to produce a particular TIFF file.

See Definition of AIP and section titled “Transforming SIPs into AIPs.”