Data storage systems are used to store, protect and manage computer data. There are many different types of products. Examples include hard drives, tape drives, floppy drives, and removable cartridge drives. Hard drives (hard disks, fixed disk drives) are located inside the computer case and use either integrated drive electronics (IDE) or small computer system interface (SCSI) circuitry. Tape drives are used to copy data from a computer onto tape cartridges. External tape drives are more expensive than internal data storage systems, but can be used with more than one computer. Floppy drives store data on 3.5 in. floppy disks. Removable cartridges have a metal or plastic housing and can be inserted and removed like floppy disks. Although removable cartridge drives are relatively fast, their speeds are usually slower than those of fixed hard disks.