What is the difference between a USB hard drive and a USB flash drive?
Answer: A USB hard drive is an external hard drive that connects via USB. It uses the same design as an internal hard drive, except comes in an external casing that protects the drive. The case also includes a USB interface, which allows you to connect the drive to your USB port using a USB cable. Most USB hard drives require a USB 2.0 connection, since USB 1.1 does not have a fast enough data transfer rate to be practical.
A USB flash drive, sometimes called a "keychain drive," also connects to the USB port on your computer. Unlike a USB hard drive, a flash drive is a "solid state" device, meaning it has no moving parts. The data is stored electronically, using millions of small gates that have a value of 1 or 0. Hard drives store data using spindles of disks that spin thousands of times every minute.
Because USB flash drives are solid state devices, they are more rugged and less prone to data loss than hard drives. However, flash drives are significantly smaller than most hard drives and cannot hold nearly as much data. Both types of storage media keep their data even when the power to the devices is turned off. However, if you want to archive data for several years, you should burn it to a CD or DVD, both of which do not require electronic charges to store data.