In order to make the information accessible to
another CD drive (or player), it has to be encoded in an
understandable form. The established form for music CDs,
called ISO 9660, was the foundation for later CD
formats. This format was specifically designed to minimize
the effect of data errors.
Photo courtesy Yamaha
The Yamaha CDR-D651, a dual-tray
stereo-component burner: With this burner, you take
music tracks directly off of another CD, instead of from
your hard drive. Burners like this are usually fast and
accurate, but typically can only be used to create music
This is accomplished by carefully arranging the recorded
data and mixing it with a lot of extra digital information.
There are a number of important aspects involved in this
- The CD track is marked with a sort of timecode,
which tells the CD player what part of the disc it is
reading at any particular time. Discs are also encoded with
a table of contents, located at the beginning of the
track (the center of the disc), which tells the player where
particular songs (or files) are written onto the disc.
- The data track is broken up by extra filler, so
there are no long strings of 1s or 0s. Without frequent
shifts from 1 to 0, there would be large sections without a
changing pattern of reflectivity. This could cause the read
laser to "lose its place" on the disc. The filler data
breaks up these large sections.
- Extra data bits are included to help the player
recognize and fix a mistake. If the read laser
misreads a single bit, the player is able to correct the
problem using the additional encoded data.
- Recorded information is not encoded sequentially; it is
interlaced in a set pattern. This reduces the risk of
losing whole sections of data. If a scratch or piece of
debris makes a part of the track unreadable, it will damage
separate bits of data from different parts of the song or
file, instead of eliminating an entire segment of
information. Since only small pieces of each file segment
are unreadable, it's easier for the CD player to correct the
problem or recover from it.
CD burners are an amazing piece of technology, and the
inner workings are certainly fascinating. But to the typical
computer user, the most compelling aspect of burners is what
you can do with them. In the next section, we'll find out how
you can put all of this technology to work and make your own