Why to Look for Disc Spanning when Choosing your Home/Office
Backup Software
Fifteen years ago, increasing numbers of people had computers,
but their important data consisted of small documents and
perhaps a few basic programs. To backup all they needed was
several blank floppy discs and a compression utility. Even a
"power user" might find themselves with two megabytes of data to
preserve.
As we collect more and more important data, our backup needs are
growing. Like in the past, we still have easily compressible
documents, but bulky multimedia files as well, like videos,
graphics and music. Doubtless this kind of data needs protection
- the first pictures or a home video of a newborn baby might
exist only as binary code on a hard drive. If your hard drive
fails and there's no backup - unlike with traditional film -
those digital memories could be lost forever. Nowdays it's
common to find full system backups of hundreds of thousands
files, ranging between 30 and 120 gigabytes (GB). The problem is
where to store this data.
There are a number of media types available to most
computer users for their backup purposes. Many businesses use
magneto-optical or large-capacity tape drives for their daily
and weekly backups. With very high capacities, these drives are
technically impressive, but the media is usually very expensive.
The common backup media for home and office includes CD/DVD
discs, dedicated internal drives and external hard drives that
exist in capacities over one terabyte (1TB) with fast Firewire
800 and USB 2.0 interfaces. Companies like Iomega found little
home market success with smaller drives such as the Jaz (1-2GB)
and Rev (35GB) series.
Where cost is a priority, a better option for home and
small business users is often disc spanning, where cheap
blank media can be used to the same effect as a tape or a
dedicated drive. The benefits in cost of disc spanning are
easily measurable. For a 20GB backup set the cost per gigabyte
(CPG) will be as cheap as 33c for a DVD-RW disc, compared with
up to $6 per gigabyte for an external hard drive of comparable
size. Even for a larger backup of 250GB the optimal cost per
gigabyte for external hard drive will be around 80 cents, still
twice more than for a DVD-RW disc. A large internal drive can
have a similar cost to a DVD-RW disc, but unless you make enough
backup sets to fill it, your excess disk space is effectively
wasted. In this sense, disc spanning is an attractive and
economical option.
This table summarizes the cost per gigabyte for different types
of storage media and various backup sets: http://www.soft
waretalks.com/files/cpg.gif.
Moreover, disc spanning is simple. All you need is to
choose the files, obtain some blank discs, and a good backup
program will inform you of the total size, and how many media
units are required for backup. Since a CD/DVD writing drive
became a part of a basic PC configuration, you don't need to
fiddle around switching external devices, adding hard discs,
installing drivers and playing other "hardware games". The
ability to store your backups on discs offsite is also a major
advantage.
Not only is disc spanning a cheap, simple and flexible backup
method, but it is also one of the most reliable backup
forms today. Modern optical storage media has a shelf life of at
least 30 years and some manufacturers even offer 100 year
guarantees. Compared to an average lifespan of 5-7 years for
hard drives and up to 20 years for a magnetic tape, optical
discs are very long-lived. Disc spanning makes it possible that
our backups will outlive ourselves.
Finally, this backup method continues to gain popularity as
technology develops. Next-generation forms of blue-laser discs
using organic dyes, such as the Sony Blu-ray format (between
23GB and 54GB) and Toshiba's HD-DVD, will further reduce the
cost of removable media, meaning that inexpensive and simple
backups are within the reach of everyone.
Article Source: http://www.sof
twaretalks.com/disc-spanning/