Page 119 - Digital Analysis of Remotely Sensed Imagery

90 Cha pte r T h ree

FIGURE 3.4 The Kingston USB memory stick with 2Gb fl ash storage memory.
It has a dimension of 9 to 10 cm by 2.5 cm by 1.2 cm. It is also highly
reliable as no parts are moveable.

Similar to a CD-ROM, this storage device is highly portable. All
desktop computers sold since 1998 are equipped with the USB sockets.
USB memory sticks are very easy and convenient to use. Once
plugged into a USB socket on a computer, a new drive is automatically
detected by the host computer running Windows 2000 or later version.
Data stored in it can then be read, and data can be written to it if the
write protection mode is turned off. USB memory sticks are preferable
to CDs because they are smaller, more reliable, and much more
flexible in data reading and recording. The same USB drive can be
used for data reading and writing without any special software,
which is standard with CD-R. Drives are not required for Windows
ME, 2000, XP, and modern Apple Macs. If running in Windows 98, the
computer must have the drive software installed.

3.2.4 Computer Hard Disk
The storage device with the longest history is the computer hard disk.
It differs from other storage media in its
• Capacity—usually very huge
• Speed—very fast
• Mobility—fixed to a computer, not easily moveable
• Cost—much more expensive

Tremendous progress has been made in the capacity, speed,
reliability, and power usage of computer hard disks. Even though the