The DOS or Disk Operating System (Disk Operating System), is an operating system designed for computers, of the Internet family, belonging to the IBM (International Business Machines), by Microsoft. This, at its inception, was supposed to be the first popular interface available for these PCs; however, MS-DOS (Microsoft Operating Disk System), surpassed it in popularity. The interface of this system was characterized by being quite simple, acting through command lines, in text or alphanumeric symbols, that is, sending an instruction by entering a series of previously established codes. Later, it would be replaced by the graphical interface of Windows.

In 1981, Microsoft buys QDOS (Quick and Dirty Operating System), to make a series of modifications, to later become MS-DOS 1.0. Over the years, the system improved, implementing the use of networks, in addition to allowing the presence of hard drives larger than 32 Gb. By version 6.0, other improvements were included, such as doublespace, which allowed disk compression , achieving more storage space, the action of a basic antivirus, a defragmenter and a memory manager were included.

With the rapid advances made in the matter, the system is completely relegated as an operating system in non-native mechanisms, and the different graphical interfaces that Windows designs are normally used. Currently, it can be found as a “command prompt”, a command program, which is executed by cmd.exe. In non-native versions, MS-DOS is still used as the basis for running the device interface.