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Fred’s Head, offered by the American Printing House for the Blind, contains tips, techniques, tutorials, in-depth articles, and resources for and by blind or visually impaired people. Our blog is named after the legendary Fred Gissoni, renowned for answering a seemingly infinite variety of questions on every aspect of blindness.

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Tuesday, May 26, 2009

CDs and DVDs

Have you sat down and tried to count the number of CDs you have at home? I have tons of disks around. Music CDs are in my CD spinners, the kids have their Playstation CDs, I have a large collection of MP3 CDs, and of course all the software I save for the computer. You may use CDs and DVDs to backup your computer information. Just how long will they last?

You may think that once you store music, documents, or photos on a CD or DVD that it will last virtually forever. That is not the case, however, as CDs and DVDs have a definite shelf life. How long CDs and DVDs will last in storage or in normal use, however, is a matter of much debate, and you cannot always trust manufacturer claims.

One organization that has studied this issue is the National Institute of Standards and Technology (NIST). The Government Information Preservation Working Group, released on December 9, 2004 a Stability Study of Optical disks that may help shed light on this issue. Please note that this document is in PDF format.

Usage Tips for Longer Life

Since CDs and DVDs don't last forever, what can you do to help prolong their life?

  • Hold CDs and DVDs by their outer edge or the middle ring. NEVER touch the bottom!
  • Don't jam media into a CD or DVD player/burner; insert it very carefully.
  • Store media in hard plastic cases; avoid wallets or sleeves.
  • Store in a room temperature environment free from moisture. Avoid keeping CDs and DVDs in extremely hot or cold temperatures for long periods of time.
  • Keep CDs and DVDs away from sunlight.

For more information, has created Archiving CD CDRW DVD DVDRW Disc.

Media Speed and Cheaper CDs and DVDs

Here's another tip for insuring that the information you save to a CD or DVD stays there.

Make sure to purchase CDs and DVDs that are rated the same or higher speed as that of your CD or DVD burner, or you will not be able to accurately burn using that media unless you manually slow down your CD or DVD burner through hardware or software.

For example, if your CD burner has a write-speed of 24X, and you purchase blank CD-Rs that are rated 16X, you will probably not be able to use those with your CD burner unless you manually slow it down. Thus, sometimes those bargain basement CDs that are being offered for pennies per media (after rebate) may not be such a bargain after all.

There are several speeds for DVDs as well. 2.4x, 4x, 8x, 16x. You should get the same speed as your DVD Burner supports. Again, if you get slower than what it supports, you will probably end up with a coaster. For example, a burner at 4x trying to burn to a disk at 2.4x. Same goes for burning a 4x disc at 2.4x. That strangely could still cause you to get a coaster.

What is -R Versus -RW?

While we're on the subject of purchasing CDs, what is the difference between these two types of CDs?

When you purchase CD-Rs or DVD-Rs, you are purchasing media that you can write to only once; you cannot erase information once it has been written to the CD or DVD. Depending on your CD software, you may be able to create multi-session CDs or DVDs where you can write to the CD or DVD once, not filling it up, then add more information to it later. However, previously written information cannot be erased.

With CD-RWs and DVD-RWs, however, provided that you have drives that support this media, you can erase information previously written to the media. You may not be able to erase and rewrite information an infinite number of times; however, it should be enough for most purposes.

To add to this confusion, there is a format called DVD-RAM that supposedly allows you to rewrite information many more times than on DVD-RWs. However, these are only compatible with a select number of drives. Plus, with DVDs there is DVD-R, DVD+R, DVD-RW, and DVD+RW, and you may not be able to use one particular DVD with a different unit that doesn't support the same standard.

The DVD Differences


DVD-R is the most compatible of the formats. This format will play in about 90% of DVD Players, DVD-Roms etc. It was the first recordable DVD format. These disks support up to 4.37GB of data. You can also get this disc double sided and expand its space to 8.75GB. This disc can be written on once and only once. Basically if it screws up, you get a nice, shiny coaster.


This format is the same as DVD-R but can be rewritten several times. This format is compatible with about 80% of DVD Players, drives, etc.


DVD+R is very simlar to DVD-R but supports a few more features, thus sacrificing compatibility. It supports lossless linking and both CAV and CLV writing. (Newbies dont worry about these features). This format is compatible on about 80% of DVD Players, drives, etc. Supports the same amount of data DVD-R does, 4.37GB and 8.75 GB Double Sided. This disc can be written on once and only once. Basically if it screws up, you get a nice, shiny coaster.


DVD+RW is the same as DVD+R but can be written to several times. It is compatible with about 70% of DVD Players, drives, etc.

DVD+R Dual-Layer

DVD+R is the same as DVD+R but supports 7.95GB on one disc. This disc achieves this by having two seperate recordable layers. This disc is the most expensive of the formats. This disc is also available in double sided format supporting up to 15.9GB of data. It is compatible in about 75% of DVD Players, drives, etc.


DVD-RAM is the least supported format. DVD-RAM usually comes in a cartridge and will not fit in most DVD-ROM drives and Players. It is compatible with about 20% of DVD Players. To my knowledge, no DVD-ROM drives support this format. Think of this format as a slow harddrive. This format is not recommended.

Which DVD is Right for Me?

Now you know about the formats but which is right for you? Well that is up to your DVD-Player. It is best to buy 1 or 2 of each format and try them out. Sometimes a DVD-Player will read DVD+R but not DVD-R. Same goes for other formats. Some DVD-Players will not read any recordable format and that's just no fun now is it. Most computer DVD drives are not picky about the disk format. They can play or record on just about any type of disk.

Generally speaking, -R media is more compatible than -RW and +RW media; for example, you may not be able to play a music CD written on -RW media on your home stereo. Also, -RW, +RW, and -RAM media may not last as long as -R media; thus, RW, +RW, and -RAM are usually used for temporary backups, working files, and the like.

Music CDs

I've never had a problem using regular data CD-R's to make music CD's. Some brands work better than others and I have heard of people that can't get them to play in their stereos.

I did some checking around and found out that the CD-R's specified for music are mainly for stand-alone CD recorders that you can hook up to your home stereo system. The recorder requires Music CD-R's because they have an extra application code built in that tells the recorder how to act.

Data and Music CD-R's use the same recording dye as data CD's so there is no difference in audio quality. Oh, and while we are on the subject of making music CD's, you can't use a CD-RW to make an audio CD to play in a regular CD player.

So, save some money and buy the regular data disks to burn music CD's for your stereo. Find a brand that works with your stereo and stick with it.

The Mini CD

Have you ever used a mini CD before? You know, they look just like a normal sized CD, but they are much smaller. They're becoming more and more popular these days and more companies are starting to use them for their software. They're also used for a lot of the computer games that are available today.

They may look cool, but have you wondered how you're supposed to use them? How can they work in your computer's CD ROM drive if they're so small?

Most CD trays have an indentation where mini CDs are placed. You just line the mini CD up and push the tray in. It will work just the same as it would if it were the bigger size. Mini CDs come in various formats as well. The normal is an 80 mm disc, which can hold about 21 minutes of music or 180 MB of data. There are also some enhanced density versions that will hold about 34 minutes of music and 300 MB of data.


  • Double Sided DVD: Both sides of the disc have a recordable surface.
  • Coaster: An object you use to place cups or beverages on.
  • Dual-Layer DVD: A disc with two recordable layers. Almost doubling the discs capacity.

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