In April 1955 the first of four IBM 704s arrived at Lawrence Livermore National Laboratory. The IBM 704, the first mass-produced computer with floating-point arithmetic hardware, was introduced by IBM in 1954. The IBM 704 Manual of operation states: The type 704 Electronic Data-Processing Machine is a large-scale, high-speed electronic calculator controlled by an internally stored program of the single address type. The 704 was thus regarded as "pretty much the only computer that could handle complex math." The 704 was a significant improvement over the earlier IBM 701 in terms of architecture and implementation. Like the 701, the 704 used vacuum tube logic circuitry. Changes from the 701 included the use of core memory instead of Williams tubes and the addition of three index registers. To support these new features, the instructions were expanded to use the full 36-bit word. The 704 could execute up to 12,000 floating-point additions per second. IBM sold 140 type 704 systems between 1955 and 1960. No photographer credited, circa 1950s.