Extending digital repository architectures to support disk image preservation and access

Abstract

Disk images (bitstreams extracted from physical media) can play an essential role in the acquisition and management of digital collections by serving as containers that support data integrity and chain of custody, while ensuring continued access to the underlying bits without depending on physical carriers. Widely used today by practitioners of digital forensics, disk images can serve as baselines for comparison for digital preservation activities, as they provide fail-safe mechanisms when curatorial actions make unexpected changes to data; enable access to potentially valuable data that resides below the file system level; and provide options for future analysis. We discuss established digital forensics techniques for acquiring, preserving and annotating disk images, provide examples from both research and educational collections, and describe specific forensic tools and techniques, including an object-oriented data packaging framework called the Advanced Forensic Format (AFF) and the Digital Forensics XML (DFXML) metadata representation.