In the early 1950’s, IBM introduced magnetic tape that essentially used magnetization on a metallic tape to store data. This was followed in quick succession by hard-disk drives in 1956, which, instead of tapes, used magnetic disk platters to store data.

The first models of hard drives had a capacity of less than 4 MB, which occupied the space of approximately two medium-sized refrigerators and cost in excess of $36,000--a factor of 300 million times more expensive related to today’s hard drives. ­Magnetized surfaces soon became the standard in secondary storage and to date, variations of them have been implemented across various removable devices such as floppy disks in the late 90s, CDs, and DVDs.

Solid-state drives (SSD), the successor to hard drives, were first invented in the mid-1950’s by IBM. In contrast to hard drives, SSD disks stored data using non-volatile memory, which stores data using a charged silicon substrate. As there are no mechanical moving parts, the time to retrieve data stored in an SSD (seek time) is an order of magnitude faster relative to devices such as hard drives.