Chapter 13. How PCs Use Light to Remember Data

How PCs Use Light to Remember Data

THE days of magnetic recording are numbered. That number might be very large, but eventually the standard for computer storage will be writing with light in some form of optical drive. We’re already doing this with recordable and rewritable CDs and DVDs, which use a finely focused laser beam to both write and read data. They sound like the same things, but there’s a difference. Data recorded on a CD-recordable (CD-R) drive cannot be erased or changed. A CD-rewritable (CD-RW) drive lets you reuse the same disc, much as you use a floppy.

Compared to a floppy disk, either type of disc is gargantuan. Each ...

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