Excerpt from the Open University course TU100 material:
So far you have seen that data itself can be remarkably resilient; its lifetime is largely limited by the medium on which it is stored. Paper rots, magnetic disks gradually lose their coatings and even optical discs are consumed by the air. Long-term threats to our data are serious enough, but we must also consider everyday threats including:
- accidentally deleting a file or program
- losing disks, computers or memory cards
- hardware failures such as a hard disk crash
- software bugs that prevent data being written to a storage device or cause it to be corrupted as it is written
- disasters such as fire or flooding
- crimes including terrorism, theft and acts of sabotage such as hacking.
Look at the list of risks to data above. Do you think any of them apply to you and your computer?
All of the above apply to most PC users, either at home or work.
Why should we migrate data regularly, and why should we make more than one copy?
Migrating data makes sure that the backup copy is relatively new, minimising the risk of it having degraded over time, and keepign any changes to the data stored to ( such as additions to your personal files, or updates to a companies trading hiistory ). Having multiple backups also helps add a layer of redundancy too the data too, and using different media would help to preserve the data against the different shorcomings of the storage media.