Launch of IBM 360 1964 (≈ 1964)
Computer revolution initiated by IBM.
1965
Creation of ISIT No. 1
Creation of ISIT No. 1 1965 (≈ 1965)
First center in Issy-les-Moulineaux.
1966-1969
Construction of ISIS No. 3
Construction of ISIS No. 3 1966-1969 (≈ 1968)
Building designed by the Montrouge Workshop.
12 mai 2015
Partial registration
Partial registration 12 mai 2015 (≈ 2015)
Fronts, roofs and fence walls protected.
5 février 2016
Complete classification
Complete classification 5 février 2016 (≈ 2016)
Building and basins classified as historical monuments.
Aujourd'hui
Aujourd'hui
Aujourd'hui Aujourd'hui (≈ 2025)
Position de référence.
Heritage classified
Inter-regional Service for the Treatment of Information (SITI no. 3), sis 2, rue Paul-Langevin, at the corner of Avenue Claude-Guillemin: the facades and roofs of the former service units contiguous to it; the fence wall on Avenue Claude-Guillemin and Rue Paul-Langevin and its entrances (Box EN 8): inscription by order of 12 May 2015. - The SITI building and the basins, with their spheres, which adjoin it, in full, as delimited by a red border on the plan annexed to the decree (box EN 8): classification by decree of 5 February 2016
Key figures
Gérard Thurnauer - Architect
ISIC Co-Conceptor #3.
André Mao - Architect
ISIC Co-Conceptor #3.
Origin and history
The Interregional Information Processing Service (SITI no. 3) is an emblematic building built between 1966 and 1969 in Orléans, in the district of La Source, by the Montrouge Workshop. It is one of the first French buildings designed to house large-scale computer systems as part of the modernization of EDF. This center was to process billing for 9 million subscribers, with IBM 370-155 machines, 13 printers and 18 magnetic tape scrollers, requiring a structure capable of supporting exceptional loads.
SITI No. 3 is part of a national network including two other sites (Issy-les-Moulineaux and Lyon), aimed at centralizing administrative management via IT. Its architecture, combining metal structure and raw concrete, reflects the technical challenges of the time: adaptation to technological changes and resistance to mechanical constraints of equipment. The building, located 2 rue Paul-Langevin, is now classified as a historical monument (2016) for its role in industrial and architectural history.
The site also includes basins with adjacent spheres, as well as functional housing and a fence wall, protected since 2015. Designed by architects Gérard Thurnauer and André Mao, it symbolizes the integration of technological innovation into the urban planning of the new cities of the 1960s. Its ranking underlines its importance as a witness to the computer revolution in France and the functionalist architecture.
ISIT #3 was dedicated to data processing for the North, East, West and West Central regions, with a capacity of 100,000 printed invoices per day. The heavy machinery and paper storage requirements imposed bold constructive solutions, marking a milestone in the history of French IT infrastructures. Today, the site remains a rare example of protected industrial architecture linked to the emerging digital age.
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