What is a hard disk more commonly known for?

A hard disk is more commonly referred to as a storage device that uses magnetic disks to read and write data. These magnetic disks, also known as platters, spin at high speeds while a read/write head moves over the surface to access the data stored. This technology has been a standard for computer storage for decades, providing a reliable way to store large amounts of data permanently or semi-permanently until they are deleted or overwritten.

The other options refer to different types of storage technologies. A solid state drive (SSD) utilizes flash memory, which offers speed advantages but does not use magnetic disks; thus, it does not fit what's commonly understood as a hard disk. A removable storage medium might include devices like USB drives or external hard drives, but these do not reflect the original definition of a hard disk. Lastly, a type of memory chip refers to semiconductor memory, such as RAM, which functions differently from a hard disk by providing temporary data storage.