(SDS 940, XDS 940) A time-sharing system, announced in February 1966, developed by scientific data systems with help from The university of california at berkeley and tymshare. SDS 940 was backward compatible with SDS's previous systems (except the 12-bit sds 92). It had monitor and user modes, dynamic program relocation, automatic memory fragmentation, and system protection.

After 1968 xerox bought out SDS and renamed the SDS machines "Xerox Data Systems" (XDS) but never actually built any.