Physical storage media

This is one of the four issues in preserving memories over time: the physical media they are stored on.

Digital data can "fade" or get lost, just like paper - only much faster. You need to:

• have backups
• renew your digital backups at intervals: every ten to fifty years depending on the medium (and get your descendants to swear to do the same)
• have backups of backups
• store some backups "offsite" i.e. somewhere else
• have backups stored in such a way as someone else can find them if something happens to you

There are many options:

1. CDs are outmoded now as a storage medium; you can't store many images or much video on one. Look to DVD. For archiving purposes stick with DVD-R/DVD-RW or DVD+R/DVD+RW. R discs can only be written to once, whereas RW discs can be overwritten later, e.g. if you update an image or document. But R discs are better for long term storage, as they last for 100 years or more whereas some RW discs last only 10. Buy good quality discs (such as those with a gold coating) for the same reason - keep the cheap ones for short-term uses. Use the pens intended for discs and don't put stickly l;abels on disks.

2. External hard-drives are another cost effective option, probably the best option right now (2008). if you store them dry and safe they will last for a long time and you can buy some enormous capacities.
3. There are some esoteric options such as Zip drives and tape drives, but you run the risk that they will not be readbale in decades to come - the more mainstream your storage format the more chance someone will find something to read it with in the year 2108.
4. Solid-state memory "drives", such as memory sticks, SD cards, and the newer "memory hard-drives", are an emerging option. They are getting up to soem uimpressive storage sizes already and the costs are plummeting. But we need to do more research on how long they retain data. Any comment from readers?

We will look at all of these in more detail in future.