Which of the following is not used for storage purposes with main frame computers?

removable disks
fixed disks
mass storage systems
diskettes E. None of the above

The correct answer is D. diskettes.

A removable disk is a data storage device that can be removed from a computer and stored elsewhere. Removable disks include floppy disks, Zip disks, and USB flash drives.

A fixed disk is a data storage device that is permanently installed in a computer. Fixed disks are also known as hard disks or hard drives.

A mass storage system is a data storage device that can store a large amount of data. Mass storage systems include tape drives, optical drives, and solid-state drives.

Diskettes are a type of removable disk that was once commonly used to store data. However, diskettes have been largely replaced by other types of removable disks, such as USB flash drives.