The introduction of the compact disc, through a joint venture between Sony and Philips in the early 1980s, greatly expanded the external storage possibilities of computers. While a floppy disk holds about 1.44 megabytes of information, a CD can hold over 600MB — over 400 times the capacity — all on one thin disk.
A CD, unlike a floppy disk, hard disk, or Zip disk, is an optical disk while the others are magnetic disks. What they all have in common is the ability to store digital data — series of 0s and 1s that computer can interpret.
The process of putting information on a CD is called burning. Special CDs, called CD-R (R for readable) or CD-RW (RW for rewritable) are used.
Here's how it works: A blank CD has a reflective surface — any light that hits it bounces off. When you burn a CD, you are shooting a laser at the surface. This laser heats up and converts tiny segments of a layer of the CD from reflective to nonreflective. This pattern of reflective and nonreflective segments is read by a CD reader as a series of 0s and 1s — digital data just like the digital data in any computer.
What Types Of CDs Can I Create?
Data and music are the two most common types of CDs people create.
A data CD is used for storing computer files. You can make your own data CD by burning files and folders from your hard disk onto a blank CD. As mentioned earlier, over 600MB of data can be put on a CD, so it is an excellent way to back up and archive important files. Because virtually every computer comes with a CD drive, it is also a good way to share files with others or move files from place to place.
A music CD is used for playing back music on a CD player. In addition to your home or car stereo CD player, a music CD can also be played on just about any computer that has a CD-ROM or CD-Recorder using freely available music player programs.
It is also possible to burn a hybrid CD, one that contains both music and data files.
What About MP3s?
MP3s are files of compressed audio signals that are about 10 percent of the size of the original file. While a typical 3-minute song on a music CD might use about 30MB of space, an MP3 of the same song will be about 3MB. So one CD with MP3s can hold 10 times as many songs as an audio CD. However, while the MP3 files on the CD are music, they are not music CDs. They are considered data CDs since they contain files that many older CD players don't recognize as music, although newer CD players are able to read MP3 discs.
How Do I Create the CD?
You need three things to burn a CD — a CD burner, CD burning software, and blank CDs. CD burners, whether internally built into the computer or externally connected, usually include the CD burning software (for example, iTunes for Macintosh or Roxio Easy CD Creator for PC). You also need blank CDs. Remember, a CD-R can only be used once for data or music storage, while a CD-RW is rewritable. Also, blank CD-R disks are significantly less expensive than blank CD-RW disks.
You begin by inserting a blank CD into the CD burner. In most cases, the CD burning software will launch automatically when you do so. If it does not, start the software manually.
When the software loads, choose the type of CD you are creating — music or data. After you make your choice, identify the files you would like burned. This is usually done by navigating through your hard disk and dragging and dropping selected files onto the list of files to be burned.
Once you've selected the files to be burned, click the "Burn," "Done," "Record," or similarly named button to initiate the burning process. The process will take a few minutes to complete, and then you will have a newly created CD.
You can label your CD on the top side by using a soft tip permanent marker.
Read other articles from the October Issue