Evans had overall responsibility for the hardware and software development of what was announced on April 7, 1964, as the IBM System/360 product line, with six models (later gradually expanded to 18 models) and a performance range factor of 50. IBM – in 1964 a company with an annual revenue of $3.2 billion – invested more than $5 billion in engineering, factories and equipment to develop and manufacture System/360, opening five plants and hiring 60,000 employees. In the lead article about System/360 in the "IBM Journal of Research and Development", April 1964, only Evans was acknowledged by name, in these words: “The scope of the compatibility objective and of the whole System/360 undertaking was largely due to B. O. Evans, Data Systems Division Vice President–Development.”