Paul Allen and Bill Gates wrote the first BASIC program for personal computers in 1975 and later founded Microsoft. That same year, The Byte Shop, one of the first computer stores, opened in California and Epson entered the US market. In 1976, Steve Wozniak designed the Apple I computer and later co-founded Apple Computers with Steve Jobs, the first 5.25-inch floppy disk was invented, Microsoft introduced an improved version of BASIC, and the first convention of computer hobbyist clubs was held in New Jersey.