Just a bit of history on haversacks from the horses mouth so to speak.
John Kincaid in his book on his experiences during the Pennisular War against the French wrote the following, "A haversack on service is a sort of dumb waiter. The mess have a good many things in common, but the contents of the haversack are exclusively the property of its owner; and a well regulated one ought never to be without the following furniture, unless when the perishable part is consumed, in consequence of every other means of supply having failed, viz. a couple of biscuits, a sausage, a little tea and sugar, a knife, fork, and spoon, a tin cup, (which answers to the names of tea-cup, soup-plate, wine-glass, and tumbler,) a pair of socks, a piece of soap, a tooth-brush, towel, and comb, and half a dozen cigars."