Monday, June 10, 2013

Exploring Your Optical Media Choices For Digital Archives

By Jim Timon


Backup comprises an important part of online solutions. It's smart to keep a digital copy of your data on some type of physical optical media. Doing so eliminates your dependence on a third-party backup service, provides a way for you to transfer data to someone else, and allows you to access your data using virtually any computer.

Two main considerations will influence your choice of which type of optical media you'll use for creating a backup of your data. First, because data storage needs have rapidly increased, you'll need to make sure you choose the media that has the storage capacity you need. Second, the media you use must be safe and dependable, allowing you to access your data for the length of time you anticipate. The current choices for creating digital archives on optical media are DVD-R, CD-R and Blu-Ray disks.

The CD-R - As a general rule, the storage capacity of a CD-R is 700mb. CD-R specifications were initially published in 1988, but the price of a CD-R recorder didn't drop below $1000 until the Philips 4020i launched in 1995. Now, however, virtually every computer includes a CD-R recorder. The average lifespan of a CD-R is about ten years, according to research conducted by J Perdereau. Many users worry about data degradation with CD-Rs, but this research shows their worries are largely unfounded.

It's important to remember that problems with optical media are usually caused by issues related to burning the data onto the disk. As soon as you burn data onto an optical media disk, check to make sure the data has copied correctly.

Most of the time, data degradation on a CD-R is caused by its reflective surface or the dyes that have been used. Over the years, both have been improved. Nevertheless, you should still closely review the manufacturer's claims regarding life expectancy. Because a gold-based reflective surface won't oxidize the way silver-based surfaces do, it's a better choice for long-term data storage.

DVD-R - These typically store 4.7GBs of data, although it is possible to get double-sided, double-layer discs that will store up to 17.08GB. The quality of the discs is a big factor in how long they will last, but in tests this has been shown to be anywhere between 2 and 15 years, with the National Institute of Standards and Technology (NIST) finding in its tests that there is greater variability with DVD-R in archival longevity then for CD-R. So, if your archival needs are modest then CD-R is probably a better choice.

The Blu-Ray - A single-layer Blu-Ray disc typically has a 25GB storage capacity, but the double-sided version can hold up to 50GB of data. Early predictions for the popularity of Blu-Ray haven't panned out, and their use isn't as widespread as anticipated. This is probably the result of rapidly increasing broadband speeds and the growing popularity of online streaming in the US. However, Blu-Ray discs provide the largest storage capacity of any of today's three optical media archiving solutions. French research into Blu-Ray lifespan determined that Sony and Panasonic Blu-Ray (HTL) discs were the most reliable for archival purposes. The same study concluded that Blu-Ray (LTH) discs were not appropriate for digital archiving purposes.

These storage solutions are cheap and they all provide an easy mechanism to create a digital archive of your data. Each type of disk is portable and reduces your reliance on a third-party archiving service. There are, however, some questions about long-term data storage using optical media. That's why I recommend having an online digital backup service in place as well as creating a physical digital archive of your data on one of these three types of optical media disks.




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