Permanence of digital data
Ensuring the permanence of digital data consists of four steps, namely backup, refresh, migrate and document. A strict routine of backup, refresh, migrate and document will ensure that important data will remain viable and can be used effectively when and where it is needed. What follows is a very simplistic view of ensuring permanence of digital data. Use it as a framework and do some research into what would suit your needs the best.
1. Backups
Backup is always the first step in making sure your data stays permanent. It is important to make at least two copies of a document on removable media. For additional safety the two copies should then be stored in separate places to guard against unforeseen accidents like fire or flood. Important documents should also be printed and filed like normal paperwork.
Think: if my house burns down, will I still have a copy?
2. Refresh
The next step is refresh. All media has a limited lifespan. It is assumed that magnetic media – a hard drive or floppy disk – can retain their data for a maximum of about five years. The magnetism simply fades away. Conversely, the life span of optic media is counted in tens of years if stored correctly. New hardware replaces old and old hardware reading old media are just not available anymore. On a regular basis, backup media should be copied to new media, followed by indexing and documentation.
Think: floppy – stiffy – cd-rom – DVD – BlueRay
3. Migrate
New versions of software are released regularly. During the migration phase, files need to be converted to the latest formats used in the organisation.
Think: WordPerfect – Office – Office97 – Office2003 – Office2007 Think: DOS – DOS/Win3.1 – Win95 – Win2000 – WinXP – Win Vista
Did you know – the newest fully patched version of Office 2007 can not open files created by Office 97? Did you know – files created by Office 2007 can not be opened by any other software on the market?
4. Document
Eventually you will have a stack of disks containing tons of safe data. But you still need to be able to find the file when you need it. At the very least, each removable disk must have a unique label. Two disks containing the same digital data as complimentary backup sets should have the same name, with one labelled as the working copy and the other as the archival copy, each kept in separate locations. Even better is the addition of a printout of the filenames that present on a disk, kept separately from the disk. If a disk is damaged or stolen, you will at least know what has been lost. Correct naming of files, be it text or images, will help in recognising the correct file when it is needed. Keeping related material together in subdirectories, adding keywords to images and then indexing all files, will help in retrieving material from archives. If you have access to advanced indexing software, you will be able to index the actual content of files. Most of us do not and have to rely on the name of the file and subdirectory to give an indication of the content. Using appropriate software, keywords can be associated with and incorporated into an image. By arranging the images into albums, indexing software can retrieve these keywords and help find and maintain large image databanks.
Think: Phonebook
Tags: magnetic media, life, old hardware, new hardware, permanence
