The challenge for electronic archive and records sector is to keep them accessible and readable in the very long term, this is the reason why many public archives institutions and research institutes and international bodies are investing to find out solutions or at least provide requirements and recommendations which will avoid unrecoverable loose of their electronic documents.
New Zealand Archives has setted an action plan for digital continuity and define it as : "Digital continuity - the ability to ensure digital information is accessible and usable by those that need it for as long as it is needed. Digital continuity conveys notions of persistence, continuation of resources, efficiency and stability. It can be seen as mitigating against the loss of, or destruction of, digital assets; or the unauthorised consumption of restricted information. Digital continuity focuses on the long-term management and exploitation of digital assets."
Digital preservation - the long-term, error free storage of digital information, for the entire time span the information is required for, through the impacts of changing technologies, including support for new media and data formats. The stored digital information must be able to decoded and rendered into usable representations, making it available for human readable access. Digital preservation focuses on the long-term storage of digital assets." http://continuum.archives.govt.nz/digital-continuity-action-plan.html
The average life of a piece of digital information is just 5 - 7 years. Vital government information is now becoming unreadable or even unrecoverable because the media it’s stored on is deteriorating, hardware and software is no longer in use, or successor products can’t read old files. For example, 5¼ inch disks, though commonplace 20 years ago, are now obsolete; cds and dvds have a finite lifespan; software used to view documents,such as WordStar, cannot easily be run on modern machines. When an electronic record becomes unreadable it is usually lost for good. That means no access to everything from inquiry findings and evidence in criminal cases, right through to budgetary and pensions information, sensitive foreign policy decisions and the location of buried nuclear waste. If you don’t take action there’s a real chance you won’t be able to access information that’s more than 5 - 7 years old.
In 1975, NASA sent two Viking space probes to Mars. The data generated by these unrepeatable missions – produced at a total mission cost of approximately $1 billion - was recorded onto magnetic tape. Two decades later, the tapes were cracking and brittle, despite climate-controlled storage, and the formats were unreadable. To access to the data, NASA had to track down old printouts and retype everything. NASA has subsequently become one of the world’s biggest supporters of digital continuity (Digital Preservation Coalition 2006).
Sixty-seven percent of New Zealand public sector agencies hold information that they can no longer access. Technological obsolescence puts public sector digital information at risk.
Failure to implement digital continuity strategies will result in irretrievable loss of information.
"An estimated 10% of the Canadian Government’s digital information is already no longer readable. A recent study by the National Science Foundation in the US found that the average cost of recreating just 20 MB of data was $64,000. In May 2006, global financial services firm Morgan Stanley agreed to pay $15 million to settle civil charges by the Securities and Exchange Commission that it failed to produce tens of thousands of emails dating back to December 2000." www.nationalarchives.gov.uk/documents/tna-digital-continuity.pdf
For further information this discussion list is very interesting! http://www.dpconline.org/graphics/links/ It carries announcements and information on activities relevant to the preservation and management of digital materials. And is intended to be a moderated low-traffic announcement and current awareness list of selected key initiatives and developments in the field of digital preservation of interest to archivists, curators, data creators, librarians and records managers both within higher education and related sectors. The archive and a joining the list web-form is available at: http://www.jiscmail.ac.uk/
And read The Handbook published by the DPC on its website "Digital information is increasingly important to our culture, knowledge base and economy. The Handbook was first compiled by Neil Beagrie and Maggie Jones and is now maintained and updated by the DPC. The handbook provides an internationally authoritative and practical guide to the subject of managing digital resources over time and the issues in sustaining access to them. It will be of interest to all those involved in the creation and management of digital materials." http://www.dpconline.org/graphics/handbook/