What is Mass Storage Media?
A mass storage medium (media being the plural) is a physical object where digital data is permanently stored, i.e. where your files are physically saved in the computer. The medium itself isn't a machine, that would be the mass storage device, which is typically called a drive.
For example, a floppy disk is a mass storage medium, while the floppy disk drive is the device that writes data to a floppy disk and can read it from the floppy disk. Similarly: a CD (Compact Disk) is the medium, and a CD drive is needed to use the CD. A hard disk drive (HDD) contains a medium called a hard disk. A USB flash drive stores data in a flash memory medium. A solid state drive (SSD) also stores data as flash memory. An even older medium than these were tapes, which would require tape drives to be used.
In general, "mass storage" is so called because the amount of data that can be stored vastly exceeds the amount of data that can be stored in the temporary RAM memory. However, note that "mass storage" from the 80's was in the range of megabytes of data, while the amount of RAM was in kilobytes. Nowadays we have gigabytes of RAM. So "mass" generally doesn't mean "massive" amounts of data, as what's massive changes every decade, it just non-volatile (i.e. permanent) storage.
Mass storage media may be removable storage or portable, which means the media can easily be removed without opening the computer's case (e.g. CDs), or it may be installed inside the computer (e.g. HDDs) by plugging it on the motherboard. In the latter case, the media is usually inside a device and isn't supposed to be removed from inside the device. However, the device may be easily be unplugged and removed from the computer's motherboard. For example, your normally install or uninstall the whole hard disk drive. You normally would never touch or even see the hard disk that is contained inside the drive.
