In 1954, FORTRAN was invented at IBM by a team led by John Backus; it was the first widely used high-level general purpose programming language to have a functional implementation, as opposed to just a design on paper. When FORTRAN was first introduced, it was viewed with skepticism due to bugs, delays in development, and the comparative efficiency of "hand-coded" programs written in assembly. However, in a hardware market that was rapidly evolving; the language eventually became known for its efficiency. It is still a popular language for high-performance computing and is used for programs that benchmark and rank the world's fastest supercomputers.