Linus Torvalds announced to the world in 1991 that he was working on "a (free) operating system" as a hobby that won't be big and professional like gnu". However, the Linux kernel was combined with GNU software to create an array of open-source operating systems that are known as Linux distributions. Today, there are an estimated 480 different distributions of Linux available. Linux is also known as the operating system that has been ported to more computing platforms than any other operating system before. Linux technology can be found on every type of computing category ranging from cell phones on the low end to supercomputers on the high-end.