A family of disk-based operating systems (Disk Operating System) for mainframes and minicomputers in the 1960s and 1970s, and subsequently IBM PCs and compatibles of the 1980s and 1990s, including MS-DOS. DO NOT USE THIS TAG FOR QUESTIONS ABOUT THE WINDOWS COMMAND PROMPT! Instead, use the [windows], [batch-file], [windows-console], and/or [cmd] tags. For questions about denial-of-service (DoS) attacks, use [denial-of-service].
DOS (Disk Operating System) is a generic name for the simplest possible operating system that can handle a disk. Examples abound from the 1950s onwards, from all major manufacturers. IBM and Digital Equipment Corporation (among others) supplied a DOS as a bootstrap operating system used to generate larger ones.
The best known and most commonly used examples of DOS are for the IBM PCs and compatibles of the 1980s and 1990s. Members of this family include Microsoft's MS-DOS, IBM's PC-DOS, Digital Research's DR-DOS, Novell DOS, FreeDOS, and others.
Between enthusiasts and legacy environments, there remains a high level of interest in MS-DOS systems and applications, whether running on real vintage hardware or under a virtual machine such as DOSBox. Programming questions about DOS are on-topic for Stack Overflow. Other types of questions should be directed to Retrocomputing.
Early consumer versions of Windows (1.x, 2.x, 3.x, the 9x series, up to Windows Millennium) were built atop of or partially based upon MS-DOS. Windows NT, Windows XP, and later do not use MS-DOS. Since modern versions of Windows are not based on DOS, questions about the Windows command prompt and batch scripts should not use this tag. Instead, use the tags windows, windows-console, cmd, and/or batch-file.
Another common usage of this acronym is for denial-of-service attacks. This is generally spelled with a lowercase "o" (DoS), and is not related to the operating system DOS. For these questions, use the tag denial-of-service. A ddos tag also exists for distributed denial-of-service attacks.
