Xerox 500 series
The Xerox 500 series is a discontinued line of computers from Xerox Data Systems (XDS) introduced in the early 1970s as backward-compatible upgrades for the Sigma series machines. Although orders for the Xerox 530 were deemed "encouraging" as of January 1974, the systems had failed to gain traction by the time Xerox sold its Data Systems Division in 1975.