In the early 1960s, Evans persuaded IBM’s chairman, Thomas J. Watson Jr., to discontinue the company’s development of a hodgepodge of incompatible computers and instead to embark on the development of a single product line of general-purpose, compatible computers. Until then, researchers thought that the fields of scientific computing and commercial data processing each required their own type of special-purpose computer. Compatibility would ensure that the same software could run on any model of the product line, avoiding a re-programming of software.