X-DDOS is a floppy disc and hard disc operating system from the german company [[Dobbertin|Dobbertin Industrie-Elektronik]]. It was first released in 1988. It provides 0.7 MB floppy disc formats for B drives and allows to access the [[Dobbertin Harddisc]] HD20. X-DDOS is delivered as a 16 KB EPROM with a lot of software and a manual.
X-DDOS has the ROM name 'XDDOS ROM' but shows a sign-on message of "X-DDOS 2.10 (C)1990 Dobbertin GmbH"