A secondary storage device holds data separately from the processor. The data stays in storage even when power to the computer gets shut off. A hard drive and an optical drive are both secondary storage devices.
A USB flash drive, usually portable and rewritable, is a type of flash memory storage device that plugs into a computer's USB port. Flash drives are more expensive than hard drives with the same storage capacity.
Floppy disks are a storage medium made of a thin magnetic disk. They were widely used from the 1970s to the early 2000s. On the 3 1⁄2-inch microfloppy, common from the late 1980s onward, storage capabilities ranged from the standard 1.44 MB to 200 MB on some versions.
A CD-R, a type of recordable CD, is an optical secondary storage device invented by Sony and Philips. It is also known as a WORM -- write once read many -- medium.
A DVD-R, a type of recordable DVD, has a storage capacity of usually 4.1 GB. There is also an 8.54-GB dual-layer version, called DVD-R DL.
Magnetic tape has been in use for more than 50 years. Modern magnetic tape is packaged in cartridges or cassettes and is used for storing data backups, particularly in corporate settings. The average amount of storage is 5 MB to 140 MB for every standard-length reel, which is 2,400 feet.