Origins of DOS

Look here to find the true record of how DOS got started on its way to becoming, for a considerable period of time, the most widely used computer program in the world. We know the facts, because our founder, Tim Paterson, wrote the first versions -- up through MS-DOS 1.25 (completed March, 1982).

Tim has also created a blog where he discusses topics such as the design of DOS and the first DOS machine. Find it at

We are now expanding this site beyond articles and excerpts. We are adding documentation of the first DOS machines, made by Seattle Computer Products.

Stay tuned and be patient while we grow this historical collection. The process is time-consuming as the original manuals are scanned, recognized, and converted to PDF while retaining the original look as precisely as possible.