 BESYS was used extensively by many departments of Bell Labs for over a decade.It was made available through the SHARE organization to others without charge or formal technical support.Versions of the BESYS environment (BESYS-3 (1960), BESYS-4 (1962), BESYS-5 (1963), BESYS-7 (1964), and BE90 (1968)) were implemented as the underlying computers transitioned through the IBM 709X family.