What is Disk Operating System (DOS)?

A disk operating system, or DOS, is a text-based user interface (TUI) that operates via a disk drive. DOSs are no longer widely used because the technology was replaced by more advanced operating systems as computing evolved, but are considered a foundational computating architecture. DOSs were generally used by hard disk drives (HDDs) and optical and floppy disks, and are characterized by a basic file system that is used to read, write, and organize files on its storage architecture. The most well-known disk operating system is called MS-DOS, which was initially developed in 1981 by Microsoft for IBM.