Microsoft Office Tutorials and References
In Depth Information
Storage Media
memory )—you can read from them, but you cannot record additional data onto them.
On a CD-R, after the data is recorded, you cannot erase or modify it, but you can add
new data to the disc, as long as the disc has not been fi nalized. In contrast, you can
re-record a CD-RW. Recordable DVD drives are also available. As with CDs, you can
buy a DVD to which you can record only once, or a rewritable DVD to which you
can record and then re-record data. Recordable DVDs come in two formats, DVD-R
and DVD+R , and likewise re-recordable DVDs come in two formats, DVD-RW and
DVD+RW . DVD drives on new computers are capable of reading from and writing to
both -RW and +RW DVDs and CDs, as well as DVDs with two layers. BD-R are Blu-ray
discs that you can record to once, and BD-RE are Blu-ray discs that you can record to
multiple times. You need a Blu-ray drive to use Blu-ray discs.
The data transfer rate of CD and DVD drives is measured in kilobytes per second
Kbps ). The original CD drives transferred data at about 150 Kbps, but newer CD drives (
can transfer data at 7200 Kbps and DVD drives can transfer data at 21,640 Kbps. CD
and DVD drives are typically classifi ed as a multiple of the speed of the original drives;
for CDs, this means 1X is the original speed (150 Kbps), 2X is twice the original speed
(300 Kbps), 4X is four times the original speed (600 Kbps), and so on. The 1X speed for
DVD drives is 1350 Kbps, so 2X is 2700 Kbps, and 16X is 21,600 Kbps.
The computer shown in the ad in the Visual Overview includes a 16X recordable/
rewritable DVD drive. It supports both the -RW and +RW formats.
Flash memory (also called solid state storage ) is similar to ROM except that it can be
written to more than once. Flash memory cards , like the one shown in Figure 13, are
small, portable cards encased in hard plastic to which data can be written and rewritten.
They are used in digital cameras, handheld computers, video game controllers, and other
devices.
Figure 13
Flash memory card
A popular type of fl ash memory is a USB fl ash storage device , also called a USB
drive or a fl ash drive . See Figure 14. USB drives for PCs are available in a wide range of
sizes from 1 to 64 GB of data. They are becoming more popular for use as a secondary
or backup storage device for data typically stored on a hard disk drive. USB drives plug
directly into the PC; the computer recognizes the device as another disk drive. USB fl ash
storage devices are about the size of a pack of gum and often have a ring that you can
attach to your keychain.
Figure 14
USB fl ash storage device
If a USB flash drive
doesn’t fit into the slot,
turn the drive over and
try again.
You’ll recommend that Elizabeth and Scott purchase a computer with a DVD drive
that can record DVDs. You’ll also recommend at least a 1 TB hard drive and at least 2 GB
of RAM.
 
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