Dependency Analysis of Legacy Digital Materials to Support Emulation Based Preservation

Emulation has been widely discussed as a preservation strategy for digital documents that depend upon proprietary executables, as well as for legacy programs. The fundamental assumption of this strategy is that an artifact (document or program) will be bundled with any required contemporaneous software in an archival information package (AIP) which can be loaded and executed in an emulation environment by patrons wishing to access the preserved artifact, yet little has been written about how to identify the required components for such an AIP. Even where a digital document was distributed with a binary viewer, there may be dependencies on other software libraries. In this paper we discuss a pilot study that performed dependency analysis for digital materials originally distributed on CD-ROM. In particular, we show how to utilize a small number of existing off-the-shelf libraries to build a tool that can analyze executables within ISO (CD-ROM) images, and then examine the results of applying this tool to a body of archived images

Assisted Emulation for Legacy Executables

Emulation is frequently discussed as a failsafe preservation strategy for born-digital documents that depend on contemporaneous software for access (Rothenberg, 2000). Yet little has been written about the contextual knowledge required to successfully use such software. The approach we advocate is to preserve necessary contextual information through scripts designed to control the legacy environment, and created during the preservation workflow. We describe software designed to minimize dependence on this knowledge by offering automated configuration and execution of emulated environments. We demonstrate that even simple scripts can reduce impediments to casual use of the digital objects being preserved. We describe tools to automate the remote use of preserved objects on local emulation environments.  This can help eliminate both a dependence on physical reference workstations at preservation institutions, and provide users accessing materials over the web with simplified, easy-to-use environments. Our implementation is applied to examples from an existing collection of over 4,000 virtual CD-ROM images containing thousands of custom binary executables

Automation of Flexible Migration Workflows

Many digital preservation scenarios are based on the migration strategy, which itself is heavily tool-dependent. For popular, well-defined and often open file formats – e.g., digital images, such as PNG, GIF, JPEG – a wide range of tools exist. Migration workflows become more difficult with proprietary formats, as used by the several text processing applications becoming available in the last two decades. If a certain file format can not be rendered with actual software, emulation of the original environment remains a valid option. For instance, with the original Lotus AmiPro or Word Perfect, it is not a problem to save an object of this type in ASCII text or Rich Text Format. In specific environments, it is even possible to send the file to a virtual printer, thereby producing a PDF as a migration output. Such manual migration tasks typically involve human interaction, which may be feasible for a small number of objects, but not for larger batches of files.We propose a novel approach using a software-operated VNC abstraction layer in order to replace humans with machine interaction. Emulators or virtualization tools equipped with a VNC interface are very well suited for this approach. But screen, keyboard and mouse interaction is just part of the setup. Furthermore, digital objects need to be transferred into the original environment in order to be extracted after processing. Nevertheless, the complexity of the new generation of migration services is quickly rising; a preservation workflow is now comprised not only of the migration tool itself, but of a complete software and virtual hardware stack with recorded workflows linked to every supported migration scenario. Thus the requirements of OAIS management must include proper software archiving, emulator selection, system image and recording handling. The concept of view-paths could help either to automatically determine the proper pre-configured virtual environment or to set up system images for certain migration workflows. View-paths may rise in demand, as the generation of PDF output files from Word Perfect input could be cached as pre-fabricated emulator system images. The current groundwork provides several possible optimizations, such as using the automation features of the original environments

Novel Workflows for Abstract Handling of Complex Interaction Processes in Digital Preservation

The creation of most digital objects occurs solely in interactive graphical user interfaces which were available at the particular time period. Archiving and preservation organizations are posed with large amounts of such objects of various types. At some point they will need to, if possible, automatically process these to make them available to their users or convert them to a valid format. A substantial problem in creating an automated process is the availability of suitable tools. We are suggesting a new method, which uses an operating system and application independent interactive workflow for the migration of digital objects using an emulated environment. Success terms for the conception and functionality of emulation environments are therefore devised which should be applied to future long-term archiving methods