What if your archive contains carriers such as CD-ROMs, floppy disks, DVDs and external hard drives? If you simply store these carriers without any additional preparation, there’s a good chance that the files saved on them will eventually become unreadable. The carriers can deteriorate or wear out over time, e.g. as a result of bit rot. There’s also a good chance that the hardware (and associated software) required to read the carrier will ultimately become obsolete. The best thing you can do in this situation, therefore, is to copy the files to a reliable storage system with as few modifications as possible. But how do you go about this?
Step 1: Draw up a list of digital carriers
- Gather together all your carriers such as floppy disks, CD-ROMs, DVDs, tapes and USB sticks, and give them all a unique number. Also collect together all information about the hardware, operating system and software that was used to create or edit the files. Compile all this information in a table, also copying across any writing that appears on the carriers.
- Store the carriers in a suitable place. If this isn’t with your physical archive and collections, take photo of the carriers where they are stored and add these photos to your physical archive and collections. Make sure you also provide the necessary references.
- Add a summary of the collected information to your archive overview.
- Draw up a priority list for transferring the files, based on four criteria:
- the importance of your digital carriers and how frequently they are used;
- the vulnerability of the carriers;
- the extent to which the information is also available in analogue form;
- the extent to which the digital version adds value compared to the analogue version.
Step 2: Transfer the files to a reliable storage system
- Estimate what storage capacity you need by grouping the carriers together per type and multiplying the number of copies you have by the capacity required for each type.
- Use a computer that you regularly scan for viruses and only use for this work.
- Create a disk image of each digital carrier.
- Document the folder structure and file information for all digital carriers (filename, size and date of modification). You can use DROID for this. Keep this documentation together with your archive and collections.
- Create and keep a checksum for each file. A checksum is a control figure calculated on the basis of the file contents. (See also Checksums as a way to monitor the integrity of files.) You can also use DROID for this. One checksum is enough for a disk image.
- Create a
readme.txtfile which documents all the above steps. Save this file in your digital archive.
- Copy your entire digital archive to a secure storage system.
- Clearly indicate on the original carriers that their contents have been transferred.
The files are safe (for the time being!) once these steps have been completed. This doesn’t mean that the digital documents will remain accessible and readable indefinitely, however. You need to research whether files can still be opened, and they must be saved in a reliable IT environment for this.
Author: Henk Vanstappen (PACKED vzw)