DOS, or Disk Operating System, refers to software that manages secondary storage devices such as floppy disks and hard disks, providing file system organization and access. The term "DOS" was coined to distinguish systems that utilized disks over older tape systems, emphasizing the advantages of faster access without the need for rewinding. Microsoft DOS, a specific implementation of DOS, was widely used until the introduction of Windows 95. While Windows operating systems also manage disks and can be considered disk operating systems, they are not the same as Microsoft DOS, which is why Windows includes a separate DOS command prompt for executing legacy commands. In early microcomputers, limited memory meant that the disk operating system was only loaded when necessary, allowing for basic disk operations otherwise. The term "abstraction" in this context refers to the way the operating system simplifies the management of storage devices, allowing users to interact with files without needing to understand the underlying hardware details.
