How Long Will Your Recordable CDs and DVDs Last?

 Digital Preservation, Digital Storage Media, Personal Archiving  No Responses »
Jan 192011
 

I recently posted some information about the short life expectancy of digital media.  Since then, I have run across another source that provides some excellent insight into the fragile existence of recordable compact discs (CD-Rs) and recordable digital versatile/video discs (DVD±Rs).

The Canadian Conservation Institute publication Longevity of Recordable CDs and DVDs provides authoritative information.  Explained are the various factors that influence how long a disc lasts, which include disc quality, recording methods, handling and storage.

I found especially useful a listing of “the relative stability of optical disc formats.”  Formats are listed from most to least stable:

  1. CD-R (phthalocyanine dye, gold metal layer)
  2. CD-R (phthalocyanine dye, silver alloy metal layer)
  3. DVD-R (gold metal layer)
  4. CD (read-only, e.g. audio CD)
  5. DVD (read-only, e.g. movie DVD)
  6. DVD-R (silver alloy metal layer)
  7. CD-RW
  8. CD-R (azo dye, silver alloy metal layer)
  9. CD-R (cyanine dye, silver alloy metal layer)
  10. DVD-RW

It is sobering to realize how many ways that optical discs can give up the ghost.  Unfortunately, other digital storage media also have their shortcomings in terms of longevity.  The best advice is still to have multiple copies of important data stored on different kinds of media.

Large drops of water on a dvd disk by Horia Varlan, on Flickr

Large drops of water on a dvd disk by Horia Varlan, on Flickr

What Obsolete Digital Media Equipment Do You Need?

 Devices and Gadgets, Digital Preservation, Digital Storage Media, Personal Archiving  1 Response »
Jan 062011
 

The first wave of desktop computers users are getting old.  As a cohort, they are retiring from their jobs, downsizing their homes and, maybe, passing on important digital data.

5.25" Floppy Disk Drive
5.25″ Floppy Disk Drive by Accretion Disc, on Flickr

Chances are good that some of this information will be stored on relics from a bygone era: floppy disks, Zip drives, tape cartridges and the like.

Any library, archives or museum–or any person–who might be the recipient of such bounty should consider their options, of which there are three:

  1. Use a commercial service to transfer the information to more modern media.
  2. Acquire some older equipment to do the job yourself.
  3. Do nothing and hope for the best.

All of these choices have associated risk.  A service can be expensive; getting your own devices can be a challenge; and doing nothing is–well, doing nothing.  A more general threat hovers over things as well: the longer the wait to transfer information, the greater the chance the original media will degrade and lose data.

Anyone who has to deal with older information might want to think about hedging their bets by acquiring  some equipment to access obsolete media.  This can be a complicated process involving a slew of gear, common and uncommon (Bernoulli Box, anyone?).

For the sake of brevity, I’d say there are four basic media readers:

These can be hard to find.  A quick search of eBay data for the past three months shows that only 49 5.25 inch drives of all types were available for sale and that “new” or “mint” drives can sell for nearly $60.

Getting a drive to read media is the beginning.  You will, of course, need to connect it to a computer. There are an alphabet soup of potential connections:  ATAPI, SCSI and USB, for example, and modern computers may not be compatible.  After hooking up an older drive, you may also need to find a specific device driver to use it. And, when everything is up and running, you will need to carefully plan how to work with the old media, whose condition is frail and content unique.

The time and effort needed to gear up for older media might make the difference between having enduring access to older information or, sadly, having no access at all.

How Long Will Your Digital Storage Media Last?

 Digital Preservation, Digital Storage Media, Personal Archiving  2 Responses »
Jan 022011
 

All digital storage media–hard drives, flash disks, CD-ROMs, and the like–have a short life.  This is why digital preservation requires active management, including regular migration of content from older storage devices to newer devices.

Do you have a back-up plan?

Do you have a back-up plan? by Images by John 'K', on Flickr

Individuals face an especially serious challenge.  Unlike many organizations, people at home typically do not have special services to guard their digital data from loss or corruption.

Another way to put it is that everyone is now their own digital archivist.  If you don’t attend to preserving your own digital photographs, videos, email, social media and so on, there is an excellent chance they will be lost.

And, unlike what some vendors imply, relying solely on the cloud is not foolproof. A commercial service can choose to pull the plug–literally–on a cloud service at any time.  If you want to keep it, you need to take responsibility for it.

Individual users need to know that the life of storage media are cut short by at least three factors:

  1. media durability
  2. media usage, storage and handling
  3. media obsolescence

Media Durability

Computer storage media devices vary in how long they last. The quality and construction of individual media items differ widely. The following estimates for media life are approximate; a specific item can easily last longer–or fail much sooner.

  • Floppy disk: 3-5 years.  Though no longer made, many still exist; examples include 8”, 5.25” and 3.5” disks, along with items such as Zip and Jaz disks.
  • Flash media: 1-10 years.  This category includes USB flash drives (also known as jump drives or thumb drives), SD/SDHC cards and solid-state drives; all generally are less reliable than traditional spinning-disk hard drives.
  • Hard drive: 2-8 years.  The health of a spinning disk hard drive often depends on the environment; excessive heat, for example, can lead to quick failure.
  • CD/DVD/Blu-ray optical disk: 2-10 years.  There is large variation in the quality of optical media; note that “burnable” discs typically have a shorter life than “factory pressed” discs).
  • Magnetic tape: 10-30 years.  Tape is a more expensive storage option for most users–it depends on specialty equipment–but it is the most reliable media available.

Media use handling and storage

People have a direct impact on the lives of storage media:

  • The more often media are handled and used, the greater the chance they will fail; careful handling can extend media life, rough handling has the opposite effect.
  • Stable and moderate temperature and humidity, along with protection from harmful elements (such as sun and salt) helps keep media alive.
  • Good-quality readers and other hardware media connections are beneficial; poor connections can kill media quickly.
  • Media that are not labeled or safely stored can be lost or accidentally thrown away.
  • Fires, floods and other disasters are very bad for media!

Media obsolescence

Computer technology changes very quickly.  Commonly used storage media can become obsolete within a few years.  Current and future computers may not:

  • Have drives that can read older media.
  • Have hardware connections that can attach to older media (or media drives).
  • Have device drivers that can recognize older media hardware.
  • Have software that can read older files on media.

What you need to do

Actively manage your important digital content!  Steps to consider:

  • Have at least two separate copies of your content on separate media—more copies are better.
  • Use different kinds of media (DVDs, CDs, portable hard drives, thumb drives or Internet storage);  use reputable vendors and products.
  • Store media copies in different locations that are as physically far apart as practical.
  • Label media properly and keep in secure locations (such as with important papers).
  • Create new archival media copies at least every five years to avoid data loss.

For more information

  1. Care and Handling of CDs and DVDs —A Guide for Librarians and Archivists
  2. Digital Media Life Expectancy and Care
  3. Do Burned CDs Have a Short Life Span?
  4. Mag Tape Life Expectancy 10-30 years
  5. Personal Archiving: Preserving Your Digital Memories (Library of Congress)
  6. Retro Media: Memory (and Memories) Lost; Which of these media will be readable in 10 years?  50 years?  150 years?
  7. Care, Handling and Storage of Removable media (UK National Archives)
  8. Do You Have a Back-up Plan?
Note: This is adopted from information developed for digitalpreservation.gov at the Library of Congress