From the introduction
You are the general of F-Troop and the Heckawees Indians are on the warpath. You must hold the fort for three days (10 commands) in order for the seventeenth cavalry to arrive with reinforcements to save the west from the Indians.
There are 1600 Indians split up so that 400 Indians are on each side. You have 120 men placed so that there are 30 men on each side. There is one cannon per side and each has 5 cannon balls. You also start with 2300 rounds of ammo.
Fort was written by D. Stanley, D. Butlien, and S. Cohen. It was published as type-in source code in Creative Computing Vol. 5, No. 8, August 1979.