What is a CD-ROM?
A CD-ROM (Compact Disk Read-Only-Memory) is a type of CD that contains data that can't be changed, because it's read-only. More specifically, when you purchased software like games in the past, you purchased CD-ROMs containing their installers. Your PC could run those installers from the CD-ROM if you had a CD drive, but you couldn't overwrite the data in the CD-ROM to store your own files in it.
