Editing Scientific Data Systems (section)

===Xerox models===
Even with these successes, when Xerox bought the company in 1969 they sold only about 1% of the computers in the [[United States]], something Xerox never seemed to improve. When they were purchased, about 1,000 SDS machines of all types were in the market, and by the time the division closed in 1975 this had increased to only about 2,100. By this point, the newer Xerox 550 and 560 models, extensively re-designed Sigmas, were about to come to market and were extensively back-ordered. Most rights were sold to [[Honeywell]] in July 1975 who produced Sigmas for a short period, and provided support into the 1980s.

Several manufacturers attempted to enter the Sigma 9 replacement market. The first successful design was the Telefile T-85, but it is not clear how many were sold.<ref>{{cite web |title=Graduate Studies Catalog |url=https://www.uwgb.edu/UWGBCMS/media/Catalog/files/1984-1986_GRAD.pdf |website=UW-Green bay |access-date=July 9, 2020 |archive-date=July 11, 2020 |archive-url=https://web.archive.org/web/20200711121245/https://www.uwgb.edu/UWGBCMS/media/Catalog/files/1984-1986_GRAD.pdf |url-status=live }}</ref><ref>{{cite web |last1=Spin |first1=William A. |title=ANNUAL HISTORICAL REVIEW KWAJALEIN MISSILE RANGE |url=https://nautilus.org/wp-content/uploads/2012/09/413-William-A.-Spin.pdf |website=Nautilus Institute |access-date=July 9, 2020 |archive-date=July 9, 2020 |archive-url=https://web.archive.org/web/20200709213228/https://nautilus.org/wp-content/uploads/2012/09/413-William-A.-Spin.pdf |url-status=live }}</ref> Other efforts, including the Modutest Mod 9, Ilene Model 9000 and Real-time RCE-9 were designed, but it is not clear if they were ever produced past the prototype stage.<ref>{{cite book |last1=McMurran |first1=Marshall William |title=Achieving Accuracy: A Legacy of Computers and Missiles |date=2008 |publisher=Xlibris Corporation |isbn=978-1-4363-8107-9 |page=104 |url=https://books.google.com/books?id=UU3v0tbq8acC&pg=PA393 |access-date=Jul 9, 2020 |archive-date=August 7, 2020 |archive-url=https://web.archive.org/web/20200807043943/https://books.google.com/books?id=UU3v0tbq8acC&pg=PA393 |url-status=live }}</ref>