DOS

1. Short for Disk operating system, DOS is an acronym often used to describe MS-DOS.

2. Short for Disk operating system, DOS refers to any operating system that runs from a disk drive. Today, all operating systems can be considered disk operating systems.

3. Short for Denial of Service, a DOS attack is a form of attacking another computer or company by sending millions or more requests every second causing the network to slow down, cause errors or shut down. Because it is difficult for a single individual to generate enough traffic for a DoS attack to be successful, these attacks are usually run from multiple computers infected by worms that have created zombie computers to all run at the same time to generate a DDoS attack.