Sunday, June 16, 2013

Exploring Your Optical Media Choices For Digital Archives

By Jim Timon


Backup is a word that has become synonymous with online solutions. Having a physical copy of your data in the form of optical media is a wise decision: it DE-centralizes the data and means that access to it is not dependent on your computer, it removes dependence on third-party backup services, and it establishes a means by which data can be independently transferred to a third party.

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.

CD-R - These typically offer storage of 700mb. The specification for CD-R was first published in 1988, but it wasn't until 1995 that the first recorder that cost less than a $1000 was introduced (the Philips 4020i). But now CD-R recorders are ubiquitous on virtually all computers. The average CD-R discs have been shown to typically last for 10 years, according to research by J Perdereau, so many people's fears about degradation are largely unfounded.

The fact that most storage problems encountered with optical media result from issues connected with the initial burning of the disc is something to always bear in mind. That's why it's so important to immediately verify the data on any newly burned optical media disk.

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.

The DVD-R - The storage capacity of most DVD-Rs is 4.7GBs of data. It is, however, possible to obtain double-layer, double-sided DVD-R discs with up to 17.08GBs of storage capacity. Disc quality has a significant impact on longevity, but research has shown that the lifespan of DVD-Rs ranges from 2 to 15 years. According to the NIST (the National Institute of Standards and Technology), the duration of archival usability of DVD-R discs is much more variable than CD-R discs. So, if you don't need the DVD-R's larger capacity, the CD-R is probably the better option.

Blu-Ray - A normal single layer Blu-Ray Disc holds 25GB of data, while a double-sided one holds 50GB. Commercially Blu-Ray has not caught on as much as was earlier predicted, largely due to the quick growth of broadband speeds and the rise of online streaming in the United States. But as an archival format it offers the greatest capacity of any of the current mainstream optical media solutions. In one French Study into its longevity it was concluded that Blu-Ray (HTL) discs produced by Panasonic and Sony offered the greatest reliability for archiving, and that Blu-Ray (LTH) discs should be avoided for this purpose.

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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