Types of Secondary Storage

Secondary storage comes in three common types: magnetic, solid state and optical. Each type uses a different method to store data, and each one has a family of devices and media that use it.

Type	How data is stored	Devices and media
Magnetic	Small areas of a surface are magnetised, and each area is set to one of two magnetic states to store 1s and 0s	Hard disk drive (HDD), magnetic tape
Solid state	Data is stored electronically in circuits, with no moving parts	Solid state drive (SSD), USB flash drive, SD card, built-in flash memory
Optical	A laser is used to read the pattern of marks on a disc	CD, DVD, Blu-ray disc

A storage type is only a category, such as solid state. A storage device or storage medium is one particular item inside that category, such as an SSD or an SD card. So an SSD is not a type of storage; it is a device that belongs to the solid state type. In the same way, a Blu-ray disc is a medium of the optical type, and magnetic tape is a medium of the magnetic type.

Keeping the two ideas apart matters because an answer has to match the wording of the question. If you are asked for a type, write solid state rather than naming an SSD, because an SSD is a device. If you are asked for a device, name something specific such as a USB flash drive rather than saying solid state. For example, a question that asks which type of storage an SD card uses is answered with solid state, because the SD card is one particular device inside that category.

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