Secondary storage is data on hard disk , tapes, and other external devices.
Primary storage is much faster to access than secondary storage because of the proximity of the storage to the processor or because of the nature of the storage devices. On the other hand, secondary storage can hold much more data than primary storage. In addition to hard disks, secondary storage includes a range of device types and technologies, including diskette , Zip drive , redundant array of independent disks systems, and holographic storage . Devices that hold storage are collectively known as storage media .