A computer is a device that stores and/or processes information. In 1937 Dr. J. V. Atanasoff and C. Berry invented the first digital computer. A few years later the military built an electronic computer. The purpose of these early computers was for simple tasks and they had no operating system. In the next 25 years, computers became more complex. Storage hardware started to appear. Additional devices that received input from the computers were also invented, like the floppy disk and printer. The more modern era of computers includes many famous names including Bill Gates and Steve Jobs. They thought of powerful concepts such as the MS-Dos system and the iPhone.