What are USB Storage Devices

By Maxwell Payne

USB Storage devices are portable devices that hold user data and files. USB storage devices include external hard drives and flash drives. These types of portable drives connect to a computer via a USB port on the computer, and can be easily moved from computer to computer. USB storage devices can be used to hold files ranging from video and audio files to documents and program files.


There are a variety of types of USB storage devices available. One kind of such device is known as an external hard drive. These drives are large capacity drives, often as big (even larger) than the drives found inside a computer. They are often powered by external power supplies, and used as backup drives to backup data on a computer.

Another type of USB storage drive is a USB Flash Drive. These small devices can fit in one's pocket and are about the size of a human thumb. They also go by the names thumb drives, flash drives and keychain drives. These drives are low-powered devices, and are powered by the USB connection.


The physical size of a USB storage device varies, and is often determined by what kind of storage medium is used. External hard drives, as their name suggests, are actual full size hard drives in a case. These drives range in size from a deck of cards to a mid-sized book.

USB flash drives use flash based memory instead of an actual hard drive, and due to this, they are smaller and lighter than external hard drives. Physically, they are about the size of a human thumb, with some being smaller or larger, depending on case design and amount of flash memory on board.

Storage wise, external hard drives often hold more gigabytes of data than a flash or thumb drive. External hard drives can range in storage size from 50GB (50 gigabytes) to hard drives that can hold multiple terabytes (such as 2TB hard drives) of data. A gigabyte contains about 1,000 megabytes and a terabyte contains about 1,000,000 megabytes of space.


Both external hard drives and flash drives function as external storage space for a user's files. External hard drives are typically used for backing up entire hard drives worth of data or for storing large files that do not need to be kept on a computer's hard drive such as movie files.

USB flash drives are typically used to move files between computers, such as loading a PowerPoint presentation from one's computer to the flash drive so that it can be accessed on an office computer. Users may also use flash drives to save work started on one computer so it can be completed later on another computer.

Both types of drives connect to a computer via a USB connection on the computer. This type of connection allows the storage device to be detected instantly and accessed immediately. There is no need to restart the computer or install special drivers to access the device.


USB storage drives should be unmounted or ejected from the system prior to physically disconnecting the device from the USB port. This ensures that any data transfers between device and computer are not interrupted. This is done by right-clicking on the USB drive icon on the computer desktop and clicking "Eject" or "Stop Device."

Users who want to back up entire hard drives worth of data should consider a large external hard drive. Those looking for a way to move small files between computers or to keep documents and files for access on the go should consider a USB flash drive.


As technology continues to advance, the storage capacity of USB storage devices is likely to greatly increase. Flash USB drives are limited by the amount of flash storage that can be placed inside the casing, but as technology for Solid State Hard Drives and smaller flash memory components improves, the storage capacity of these thumb drives is expected to grow.