is a situation where a digital resource is no longer readable because the physical media, the reader required to read the media, the hardware, or the software that runs on it, is no longer available. A prime example of this is the BBC Domesday Project
The BBC Domesday Project was a partnership between Acorn Computers Ltd, Philips, Logica and the BBC to mark the 900th anniversary of the original Domesday Book, an 11th century census of England...
. Cornell University Library’s digital preservation tutorial
(now hosted by ICPSR) has a timeline of obsolete media formats, called the “Chamber of Horrors”
, that shows how rapidly new technologies are created and cast aside.
The rapid evolution and proliferation of different kinds of computer hardware
Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....
, modes of digital encoding, operating systems and general or specialized software ensures that digital obsolescence will become a problem in the future. Many versions of word-processing programs, data-storage media, standards for encoding images and films are considered "standards" for some time, but in the end are always replaced by new versions of the software or completely new hardware. Files meant to be read or edited with a certain program (for example Microsoft Word
Microsoft Word is a word processor designed by Microsoft. It was first released in 1983 under the name Multi-Tool Word for Xenix systems. Subsequent versions were later written for several other platforms including IBM PCs running DOS , the Apple Macintosh , the AT&T Unix PC , Atari ST , SCO UNIX,...
) will be unreadable in other programs, and as operating systems and hardware move on, even old versions of programs developed by the same company become impossible to use on the new platform (for instance, older versions of Microsoft Works
Microsoft Works is an integrated package software that is produced by Microsoft. Works is smaller, less expensive, and has fewer features than Microsoft Office or other major office suites. Its core functionality includes a word processor, a spreadsheet and a database management system...
, before Works 4.5, cannot be run under Windows 2000
Windows 2000 is a line of operating systems produced by Microsoft for use on personal computers, business desktops, laptops, and servers. Windows 2000 was released to manufacturing on 15 December 1999 and launched to retail on 17 February 2000. It is the successor to Windows NT 4.0, and is the...
Early attention was brought to the challenges of preserving machine-readable data by the work of Charles M Dollar
Charles M Dollar, an internationally recognized expert on the life cycle management of electronic records, particularly electronic records archiving, pioneered research into digital preservation of electronic records. He holds a Ph.D...
in the 1970s, but it was only during the 1990s that libraries and archives came to appreciate the significance of the problem and has been discussed among professionals in those branches, though so far without any obvious solutions other than continual forward-migration of files and information to the latest data-storage standards. File formats should be widespread, backward compatible, often upgraded, and, ideally, open format. The National Initiative for a Networked Cultural Heritage cites the following as “de facto” formats that are unlikely to be rendered obsolete in the near future: uncompressed TIFF and PDF (for images) and ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
The Rich Text Format is a proprietary document file format with published specification developed by Microsoft Corporation since 1987 for Microsoft products and for cross-platform document interchange....
Copyright is a legal concept, enacted by most governments, giving the creator of an original work exclusive rights to it, usually for a limited time...
issues also presented a significant challenge for projects attempting to overcome the obsolescence issues related to the BBC Domesday Project. In addition to copyright surrounding the many contributions made by the estimated 1 million people who took part in the project, there are also copyright issues that relate to the technologies employed. It is likely that the Domesday Project will not be completely free of copyright restrictions until at least 2090.
In some cases, obsolete technologies are used in a deliberate attempt to avoid data intrusion in a strategy known as "security through obsolescence".