Monday, May 06, 2013

Light, Dark and Dim Archives: What are they?

Light, Dark and Dim Archives: What are they? Chris Erickson. May 2013.
     The following is a compilation of a few definitions or examples of Light, Dark and Dim archives to better understand what they are. 

The notion of "dark archives", supporting little or no access to archived materials, has met with scant enthusiasm in the library community. This suggests that digital repositories will function not just as guarantors of the long-term viability of materials in their custody, but also as access gateways. Lavoie

A secure digital repository sometimes referred to as a "dark archive" Kirsch

Dark Archive: An archive that does not grant public access and only preserves the information it contains. This can refer to a digital archive or repository as well as brick & mortar archive. Michigan

Dark archive: The purpose of a dark archive is to function as a repository for information that can be used as a failsafe during disaster recovery. UCPress

The Dark Archive is a secret place for storing archival material with restricted user access. Tufts

We chose to create a “dark” archive to focus our efforts on securing and preserving large volumes of content important to libraries and their users; however, it is not exclusively dark. Participating libraries experience the archive as a “light” or accessible archive in two ways: auditing the archive to ensure we are prepared to support eventual use and accessing of content that has been made available as the result of a “trigger event” or post-cancellation access claim. Portico

Dark archives are certainly misunderstood both inside and outside the industry.  So, what is a dark archive?  It is, simply put, an archive of information that is not used for public access.  Most often it serves as a failsafe copy of a light archive, i.e. a publicly available version of the information, for use in disaster recovery operations.  Dark archives need not be a fully operational copy of an information system, rather just the content behind the information system.  This is an important distinction because maintaining an exact operational copy of an information system is a much more complex and expensive undertaking than maintaining only the content the information system operates on.  Metaphorically, at its base definition, a dark archive will require more than a flip of the switch to make a light archive. Osti Bog

Dark Archive: An archive that is inaccessible to the public. It is typically used for the preservation of content that is accessible elsewhere. See also dim archive, light archive.
Dim Archive: An archive that is inaccessible to the public, but that can easily be made accessible if required. It's typically used for the preservation of content that is accessible elsewhere. See also dark archive, light archive.

Light Archive: An archive that is accessible to the public. See also dim archive and dark archive.  CDL

A DDP network may be an open archive, or it may reside somewhere on the spectrum from dim to dark archive. That is, it may be open to only the contributors’ servers for ingesting (dark archive); it may be open to specified users, such as the contributing institutions’ communities (dim archive); or it may provide unrestricted access (open archive). This status will determine whether contributors will focus solely on long-term preservation issues, or some combination of preservation and public access issues. MetaArchive

Dark Archive: Digital archive for which access to content is limited to organizational custodians.
Dim Archive: Digital archive that incorporates elements of both the Dark and Open Archive models. Access for some materials is restricted to organizational custodians, while access for others may be open to a broad user community.
Open Archive:  A digital archive that is publicly accessible. MetaArchive

 Below are two figures from the OAIS Model (2012) showing the Access functions.

Figure 4-1: OAIS Functional Entities

Figure 4-7: Functions of the Access Functional Entity


Adam Carter said...

An interesting summary of definitions, thanks! I note you include diagrams from the OAIS model at the end. Would you consider a dark archive to basically be an implementation of this model without the "Access" box?

John Barness said...
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