Welcome to my FreeDOS Workshop. FreeDOS is an open source project aimed at creating a free, open sourced version of DOS. It aimed to be compatible with Microsoft's MS-DOS 3.3 for now at least, and it's doing quite well. Find out more at www.freedos.org.
I've added support to FreeCOM (COMMAND.COM) to allow MS-DOS-style F1, F3 and F5 keystrokes, which I keep (trying) to use. There are some bugs, but they will be sorted out in time. Visit http://sourceforge.net/projects/freedos/ for more information.