DR DOS or DRDoS may refer to any of the following:
1. DR. DOS, also known as DR-DOS, is an operating system developed by Digital Research for IBM-compatible computer systems. The first version of DR DOS, version 3.31, was released on May 28, 1988. It supported the FAT16B file system, also known as BIGDOS.
2. DRDoS is an abbreviation for DNS distributed reflection denial of service. It is a type of DoS (denial of service) attack on a networked computer. It often uses UDP (user datagram protocol) to make calls using DNS (domain name system), NTP (Network Time Protocol), and other server protocols to a target IP address.