Realtime Disk Operating System A developed in the 1970s or 1980s. When used in conjuction with a (e.g. ) it could support 16 concurrent users at the level and two printers all on 128K memory. Reputedly wanted to license this for the first but DG turned them down so they went to instead. How different the world could have been. [Before or after IBM wanted ?] (1997-11-23)