Microsoft Office Tutorials and References
In Depth Information
Optical Discs
A USB flash drive , sometimes called a thumb
drive, is a flash memory storage device that plugs
into a USB port on a computer or mobile device
(Figure 24). USB flash drives are convenient for
mobile users because they are small and light-
weight enough to be transported on a keychain or
in a pocket. Current USB flash drives have stor-
age capacities ranging from 512 MB to 64 GB.
An ExpressCard module is a removable
device, about 75 mm long and 34 mm wide or
L-shaped with a width of 54 mm, that fits in
an ExpressCard slot (Figure 25). ExpressCard
modules can be used to add memory, storage,
communications, multimedia, and security capa-
bilities to a computer. ExpressCard modules
commonly are used in notebook computers.
Figure 24
A close-up of the flash memory and circuitry inside a USB
flash drive.
two sizes of
Figure 25
ExpressCard modules are available in two sizes.
Optical Discs
An optical disc is a flat, round, portable metal disc with a plastic coating.
CDs, DVDs, and Blu-ray Discs are three types of optical discs. A CD can
hold from 650 million to 1 billion characters. Some DVDs can store two
full-length movies or 17 billion characters. Blu-ray Discs can store about
46 hours of standard video, or 100 billion characters. Optical discs used in
personal computers are 4.75 inches in diameter and less than one-twentieth of
an inch thick. Nearly every personal computer today has some type of optical
disc drive installed in a drive bay. On some, you push a button to slide out a
tray, insert the disc, and then push the same button to close the tray; others
are slot loaded, which means you insert the disc in a narrow opening on the
drive (Figure 26).
Figure 26
A slot-loaded optical disc drive.
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