USB flash memory drives are known by many names, both generic and trademarked. These devices are sometimes called keychain drives, watch-fob drives, key drives, pen drives, pocket drives, USB sticks, memory sticks, flash drives, USB mass storage drives, and so on. To the displeasure of the manufacturers, trade names for these devices are often used generically, including ThumbDrive (Tech 2000), JumpDrive (Lexar), and Gizmo! (Crucial Technology). Whatever you call them, they've become ubiquitous.
Figure 9-5 shows a collection of typical USB flash drives, with a Swiss Army Knife (not one of the models with a flash memory drive incorporated) shown for scale. The flash drives on the left are inexpensive and reliable Crucial Gizmo! units. Those on the right are a Kingston DataTraveller II (top) and the premium DataTraveller Elite.
Figure 9-5. Typical USB flash drives
USB flash drives are conceptually simple. They comprise a physical housing that contains a USB interface connector, some flash memory, and the circuitry needed to interface the memory to the USB connector. Some drives include additional circuitry, such as support for hardware-based encryption or an LCD display. The drive plugs into and is powered by a USB port, and the flash memory is nonvolatile. Data written to the USB flash drive is retained permanently until it is manually deleted or overwritten. ...