Critically Endangered small

Materials saved to DVDs, CDs or other optical storage devices where the media is out of warranty and reader devices may no longer be supported or integrated easily into hardware infrastructure: typically more than five years old.

Group: Portable Media

Trend: New Entry

Consensus Decision

Added to List: 2019

Last update: 2019

Previous category: New Entry

Imminence of Action

Action is recommended within three years, detailed assessment is in 12 months

Significance of Loss

The loss of tools, data or services within this group would impact on many people and sectors.

Effort to Preserve

It would require a major effort to prevent losses in this group, including the development of new preservation tools or techniques


CDs, laser disc technologies, DVD, HDVD

‘Practically Extinct’ in the Presence of Aggravating Conditions

Poor storage; inability to access readers; no replication; encryption

‘Endangered’ in the Presence of Good Practice

Active management; dependable access to readers; strong documentation; documentation independent from the media

2019 Review

The judges have introduced this entry to ensure that the range of media storage is properly assessed and presented.  Optical media is in some senses a preferred option as it is typically more stable than magnetic or solid state media: but these characteristics have been over-sold.  The substrates of the disks can prove unstable and more importantly the reader technology tends to be proprietary and can become obsolete long before the disks degrade. Storage at scale also means the percentage likelihood of failure increases.

Additional Jury Comments

Highly dependent on who is looking after the portable media but made more difficult over time. There is a lack of granularity in the definition of media types so generic advice like "make sure you're moving your data to new forms of storage every 5 -10 years".

Early generations of this media are not as robust as the current generation and can deteriorate significantly if not stored appropriately.

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