LANL’s Time Travel Portal, Part 1

Early February 2015, we launched the Time Travel portal, which provides cross-system discovery of Mementos.

The design and development of the Time Travel portal was a significant investment and took about a year from conception to release. It involved work directly related to the portal itself, but also a fundamental redesign of the Memento Aggregator, the introduction of several RESTful APIs, the transfer of the Memento infrastructure from LANL’s network to the Amazon cloud, and operating the new environment as an official service of the LANL Research Library.

The team that designed and implemented the Time Travel portal, from left to right: Luydmila Balakireva, Harihar Shankar, Martin Klein, Ilya Kremer, James Powell, and Herbert Van de Sompel
The team that designed and implemented the Time Travel portal, from left to right: Luydmila Balakireva, Harihar Shankar, Martin Klein, Ilya Kremer, James Powell, and Herbert Van de Sompel

A major motivation for the development of the new portal was to lower the barrier for experiencing Memento’s web time travel. Our flagship Memento for Chrome extension remains the optimal way to experience cross-system time travel. But, we wanted some of the power of Memento to be accessible without the need for an extension.

The Time Travel portal has a basic interface that allows entering a URI and a datetime. It offers a Find and a Reconstruct service:

  • The Find service looks for the Mementos in systems covered by the Memento Aggregator. For each archive that holds Mementos for the requested URI, the Memento that is temporally closest to the submitted date-time is listed, with a clear indication of the archive’s name. Results are ordered by temporal proximity to the requested date-time. For each archive, the first/last/previous/next Memento are also shown when that information is available. For all listed Mementos, a link leads straight into the holding archive. A Find URI can also be constructed. Its syntax follows the convention introduced by Wayback software, e.g.
  • The Reconstruct service reassembles a page using the best Mementos from various Memento-compliant archives. Hereby, “best” means temporally closest to the requested date-time. Hence, in a Reconstruct result page, the archived HTML, images, style sheets, JavaScript, etc. can originate from different archives. Many times, the assembled pages look more complete and the temporal spread of components is smaller, when compared with corresponding pages in distinct archives. As such, the Reconstruct service provides a nice illustration of the cross-archive interoperability introduced by the Memento protocol. A Reconstruct URI is available using the same Wayback URI convention, e.g.

While the Time Travel portal has been received enthusiastically, usage remains modest. Since its launch, we have seen about 4000 unique visitors, 7000 visits, per month. We have capacity for much more and would appreciate some promotion of our service by IIPC members. Also, we are very open to suggestions about additional portal functionality. For example, we have reached out to IIPC members that operate dark archives because we are interested in including their holding information in Time Travel responses, in order to increase response completeness and to make the existence of these archives more visible. As a first step in that direction, we have proposed Memento-based access to dark archive holdings information as a new functionality for Open Wayback.

By Herbert Van de SompelDigital Library Researcher at Los Alamos National Laboratory

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