DOS

1. Disk Operating System: a disk-based operating system, usually referring to MS-DOS. Originally developed by Microsoft for IBM, MS-DOS was once the standard operating system for IBM-compatible personal computers. 2. Denial of Service: a type of attack on a network that is designed to bring the network to its knees by flooding it with useless traffic. 3. Department of State: a federal or state governmental department handling issues central to the country or each of the individual States, such as travel, tourism, elections, charters and licensing, historic records, and overall public security. 4. Department of Safety: a department used by some U.S. states and cities which usually handles driver and vehicle, police, enforcement, fire, corrections, and crime statistics services for the public. 5. Department of Statistics: a department used by some countries for handling statistical reports vital to their economies and governments.