Your hard disk might not be the ideal place for storing all the information you generate. Part of the data in your pc could pertain to financial records, investment details, bank accounts, credit card information, etc. Such details can get misused if wrong people access your data.
Vital information is best stored in another data storage device that can be kept secure in an off-site location (if necessary). Data CD is one such media that has been universally accepted. You can store all kinds of information, in the form of word processing documents, spreadsheets, graphics, text files, etc. Your CD has a storage capacity of 650 to 700 MB.
Data Storage CD
When we refer to data storage CDs what we mean is the CD-RW. This is the preferred device for storing information for it can be rewritten plenty of times. However, quite frequently, many people use the CD-R for data storage for it costs lesser. Data entry can take place till the maximum capacity is reached. After the existing data storage capacity is exhausted, people simply buy a new CD, so even CD-R can be called a data CD. These compact disks CD-R and CD-RW are widely used for their longevity.
Longevity of a CD
Manufacturers often predict that CDs are expected to last a few hundred years. They subject their product to ‘accelerated aging tests,’ and gauge the approximate life span of the media, based on these results. Artificial tests are required for CDs for they are of comparatively new technology and their longevity cannot be naturally verified. However, the actual life span of a CD does not conform to the forecasted rate in all the cases.
Factors that Affect Longevity of a CD
- CDs that have manufacturing defects cannot last even if all the other external conditions are ideal.
- CDs contain four layers, substrate, and a dye layer over it, a metal layer and finally a protective coating. All the layers other than the metal layer contain organic compounds. These compounds can degrade due to changes in their chemical structure. Deterioration of the dye layer leads to data destruction.
- Even rapid changes in the environmental conditions induce mechanical stress. This might cause excessive birefringence.
- Even writing on the CD label with permanent ink for easy identification might damage it. Permanent markers release volatile organic compounds. As they remain trapped inside the casing they destroy the CD.
A few precautions might help you protect your CD and prevent data destruction.
Necessary Precautions for Safeguarding CDs
If you want the data contained on your CDs to last long, keep them away from water, ink, radiation, heat, dust, etc. These pollutants damage CDs.
Always mark your labels using water-based inks and write on the clear inner ring of the CD.
The speed of writing data also determines how long it might last. Low speed writing using good recorders produce data that longs last. These precautions should be adequate, yet, if you lose the data stored on your CD, try cleaning the device.
Cleaning a CD
Clean your CD using distilled water as tap water may contain impurities. Do not use solvents such as alcohol. Take a soft cloth, (which is devoid of hard fibres) and wipe from the centre outwards. Dry it immediately and do allow your CD to remain wet.
You might also lose data if your CD gets scratched. Do not attempt to remove the scratches using toothpaste or any other material. Polishing the surface does not remove the scratch. It only replaces one large scratch with multiple scratches which leads to a reduction in the intensity of the laser beam.
The substrate of the CD is polycarbonate and polishing reduces the thickness of the substrate. This results in modification of the optical path length. Substances other than polycarbonate have different refraction index. This causes optical distortion when laser beams are focused.
Even after cleaning the CD, if you are not able to recover the data, you have to use the data recovery software.
Data Recovery Software
The optical media data recovery software tool works for CDs, DVDs, HD DVDs, etc. First download the data recovery software and load the damaged CD in your pc. The software will immediately reveal all the tracks and sessions on the media along with the file systems. Select the data you want to retrieve and transfer it to the hard drive.
If even the data recovery software fails to give the desired results, you might have to approach data recovery service providers. However, prevention is better than cure. Handle and store your data CDs well to prevent such occurrences.
Computer forensics (or digital forensics) experts can examine a hard drive to determine whether there has been unauthorised interference with the disk (i.e. hacking).