DOS , short for disk operating system, is an acronym for several computer operating systems that were operated by using the command line.

DOS is a family of operating systems for x86-based computers, most commonly IBM PC-compatibles.

In computing, a denial-of-service (DoS) attack is an attempt to make a machine or network resource unavailable to its intended users, such as to temporarily or indefinitely interrupt or suspend services of a host connected to the Internet. A distributed denial-of-service (DDoS) is where the attack source is more than one–and often thousands of-unique IP addresses.

In computing, a directory is a file system cataloging structure which contains references to other computer files, and possibly other directories. On many computers, directories are known as folders, catalogs (catalog was used on the Apple II, the Commodore 128 and some other early home computers as a command for displaying disk contents; the filesystems used by these did not support hierarchal directories), or drawers to provide some relevancy to a workbench or the traditional office file cabinet.

¡Dos! is the tenth studio album by the American punk rock band Green Day. The album was released on November 9, 2012 in Australia, November 12 in the United Kingdom and on November 13 in the United States through Reprise Records. It is the second installment in the ¡Uno! ¡Dos! ¡Tré! trilogy. Following its predecessor's pop punk style, ¡Dos! was billed as Green Day's take on garage rock.