How Does an External DVD Burner Work?by Stephen Lilley
Differences from an Internal Burner
The major difference between an internal DVD burner and an external DVD burner is that the internal one must be plugged in and inserted into the tower of your computer, while you can set an external DVD burner on a shelf somewhere or wherever you happen to want it. An external DVD burner connects to your computer via either a USB or Firewire cable. These cables are used to transmit data from your hard drive to the computer.
The external DVD burner will use a blank DVD the same way an internal one would. Once the disk is in the tray and the drive is closed, the disk begins to spin, because the laser that is used by the drive to write to and read from media can only access all information if the disc is spinning.
On a blank DVD with a single layer, a user can fit 4.8 gigabytes of information. With a blank dual layer DVD, a user can fit over 9 gigabytes of information on one disk. A special drive will be required to write to dual layer media, however, as it needs a special laser that can change between the two. When a user finalizes files she wants to write to a CD, the computer transfers all the data into a signal that can be transmitted via the drive's laser. The data is then sent from the computer to the drive via the USB or Firewire cable.
The laser transfers all data to the disc until each available layer is full. The drive then finalizes the writing process, which means that the disc can no longer be changed unless it is rewritable media and you were burning with a rewritable drive (which, like dual layer media, requires the drive to have a special laser). The disc can then be accessed on any DVD drive that is connected to a computer.
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