Which storage device is known for being non-volatile?

The non-volatile nature of a storage device means that it retains data even when the power is turned off. A hard disk drive (HDD) is indeed non-volatile because it uses magnetic storage to write data onto spinning disks, ensuring that the information remains intact without requiring a continuous power supply. This characteristic makes hard disk drives suitable for long-term storage of files, applications, and operating systems, as users can shut down their computers and still have access to their data later.

In contrast, devices like Random Access Memory (RAM) are volatile, meaning that they lose all stored data when the power is turned off. Flash drives and optical disks are also non-volatile storage options, so the selection of HDD is appropriate in a context where we are discussing the most traditional and widely recognized forms of non-volatile storage that has been in use for an extended period.