In my previous article I conducted a test to see how durable CD’s and DVD’s are. This is a crucial consideration if you are thinking about using such media for backup purposes. This article contains tips and recommendations for using optical media as backup media. Conclusions are based on 15 years of computing experience and the previously mentioned test I did.
Choosing a backup media
Ever since the CD recorder made its appearance, later to be replaced by DVD burners, they have played a major role in backing up our data, especially for home users that could not afford “real” backup solutions. For a long time I thought that BluRay would take over as the backup media of choice, but the recent developments in storage technology have made optical media less interesting for backup purposes. Hard drives have now become so large that they out-compete optical discs as storage media in terms of cost per megabyte, as well as agility and speed(!) They are however more sensitive to shocks and other harsh conditions. USB memory sticks and online backup services offer a simple solution if you don’t require wast amounts of storage capacity. My first recommendation is thus to think about your needs and calculate the cost of various options.
Making your backups
If you still choose to use CD/DVD for backuping important data, remember that optical media degrade with time. The tricky part is that you can never really tell the condition of a disc until you try to read it. You need to be aware of this and take precautions to prevent data loss. For example you could burn multiple discs with the same content, or re-burn the collection from time to time, depending on your individual need.
Brand name discs are no guarantee for high quality, but usually better than less known and no-name brands. And don’t forget to store your discs properly. They prefer dark and dry places. Direct sunlight and humidity will damage them!
Reading back the data
Different drives are differently good at reading, especially when it comes to troublesome data. This is probably both a case of the hardware and firmware (internal software) in the reader. My advice is to try several different readers before you discard a disc if the content is valuable to you. If a the reader does not seem to find the disc, try to eject it and put it back in again a few times, as the drive may have better luck locating the tracks this time. Also make sure you to polish the disc just in case there’s some smudge on it.
You should avoid copying files from problematic CD’s using Windows Explorer. When read errors occur it usually cancel the entire copy operation, which is very frustrating. I can recommend two programs for reading. First there is Unstoppable Copier, which is specifically built to handle discs with read errors. Another favorite is classic file manager Total Commander, which works fine in most cases, although it does not have the same level of logging and retry management as Unstoppable Copier.
If you have an older computer and copying CD’s is slow, you may want to check the DMA settings to make sure it is turned on. If not, try to uninstall the IDE channel using the Device Manager and restart your computer. Windows should find the hardware again, and hopefully the DMA will be correctly setup this time. This trick worked for me at least, giving me four times the reading speed and also reduced the CPU load to a minimum!