(1) See USB drive.
(2) A disk or disk cartridge that is inserted into the drive for reading and writing and removed when not required. Using optical technologies, CDs and DVDs are the common examples. Removable Hard Disks Before the Internet became a common transport mechanism, and prior to the widespread use of portable USB-based hard drives, various magnetic disk drives with removable cartridges were made for backup and transport. All such products exceeded the extremely limited capacity of the floppy disk. See Zip disk, REV disk, magnetic disk and optical disc.