USB Drive Key Terms

Learn important USB drive terminology to better understand the device

USB drives are fast replacing CDs and DVDs as the computer storage and backup method of choice. USB flash drives, or thumb drives, are small, portable storage devices that are great for carrying important documents or utilities with you from location to location. External USB hard drives are an excellent way of backing up the existing data on your computer. While not as portable, they can store a larger amount of data than their smaller counterparts. Learn how USB drives work by understanding the terminology associated with them.

Flash drive

A USB flash drive doesn't have moving parts like a typical hard drive, or external USB drive. It is called a drive because it interacts with the computer by using the same commands as a normal drive. A flash drive is comprised of a small, printed circuit board enclosed in a case, with a USB connector that is either retractable or protected by a removable cap. Data is stored in NAND-type flash memory.

Flash memory

Flash memory is a type of memory that requires no power to maintain the information on the chip. It is a sub-type of EEPROM (Electrically Erasable Programmable Read-Only Memory) that can be erased and reprogrammed in blocks, rather than all at once. Because of its extreme durability under pressure, heat and water, flash memory has become the memory of choice for MP3 players, USB drives and memory cards.

NAND and NOR

NAND and NOR are both types of flash memory invented by Dr. Fujio Masuoka circa 1980, when he worked for Toshiba. NOR flash memory is typically used to store and run small amounts of code. NAND flash memory is better suited for high-capacity data storage. For this reason, most USB flash drives use NAND technology.

USB, or universal serial bus

Both USB flash drives and external USB hard drives use universal serial bus technology to connect to your computer. USB 1.0 was released in 1995, and had a top connection speed of 12 Mbps (megabits per second). The current standard is USB 2.0, which operates at 480 mbps. Most USB drives now use USB 2.0 connections. USB 3.0 is currently under development, and will support speeds of 5Gbps (gigabits per second), with lower power specifications and improved efficiency.

USB hard drive

A USB hard drive is basically just an external hard drive. It is a standard EIDE or SATA based hard disk-exactly like the one found inside your computer-encased in a solid enclosure. The enclosure can then be connected to your computer using either USB or FireWire. Most companies manufacture external USB hard drives in sizes up to one terrabyte, or 1000 gigabytes.

Hard drive enclosure

Any SATA or EIDE hard drive can be turned into an external USB drive by using a hard drive enclosure. If you purchase a new tower, and still have data that you need to be able to access on an old laptop or desktop hard drive, you can simply purchase an enclosure and turn that drive into a portable USB storage device.

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