The history of computers dates back to the 1800s with the development of various computing machines by scientists, leading to the creation of the first programmable computer, the Z1, by Konrad Zuse in the 1930s. Other significant milestones include the Z3, the Atanasoff-Berry Computer capable of storing data, the Harvard Mark-1/Colossus used during WWII, and the ENIAC created for ballistic analysis. Transition from vacuum tubes to transistors occurred in the 1950s, with the development of the Manchester TC and the introduction of the COBOL computer language by Grace Hopper. IBM launched the IBM 701 and later the successful IBM 360 series. The first desktop computer, Program 101, was sold in 1965, while the DDP-116 marked the development of 16-bit microcomputers. In 1970, Intel released the first dynamic access memory chip (DRAM), and IBM invented the floppy disk in 1971. The Altair 8800, featuring the BASIC programming language by Bill Gates and Paul Allen, became popular upon its launch in 1975.