HOW TO CREATE A FREEDOS BOOT DISK:
1. Download the FreeDOS boot disk image:
2. Extract fdodin06.144 from the zip file.
3. Insert a floppy disk.
4. Launch a terminal session in Linux.
5. Type cat fdodin06.144 > /dev/fd0
And a good place to pick up all sorts of abandoned DOS programs to run in FreeDOS (like WordStar or Norton Commander) is http://vetusware.com/.
The SimTel MS-DOS shareware archive is mirrored in many locations, one can be found here: http://www.eunet.bg/simtel.net/msdos/index-msdos.html
Sometimes old school is best. I have a DOS astronomy program called Skyglobe I've used since 1993 (see below), it works like a champ and it's amazing. I learned to program the Trash-80 in 1978, and the Apple II later. My mind has been mangled by the use of GOTO statements in GW-Basic, I can never learn C. It's too late for me. But I have PowerBasic, which used to be Borland Turbo Basic (I have that too), and I still use it to write software. But it only runs in DOS. Under Linux, DOS programs can be run in DOSBox but the graphics are very slow. FreeDOS is a great alternative.