From Wikipedia:
"There are various theories concerning the origin of the term "cracker".
The term "cracker" was in use during Elizabethan times to describe braggarts. The original root of this is the Middle English word crack1 meaning "entertaining conversation" (one may be said to "crack" a joke); this term and the alternate spelling "craic" are still in use in Ireland and Scotland. It is documented in Shakespeare's King John (1595): "What cracker is this same that deafs our ears with this abundance of superfluous breath?"
By the 1760s, this term was in use by the English in the British North American colonies to refer to Scots-Irish settlers in the south. A letter to the Earl of Dartmouth reads: "I should explain to your Lordship what is meant by Crackers; a name they have got from being great boasters; they are a lawless set of rascalls on the frontiers of Virginia, Maryland, the Carolinas, and Georgia, who often change their places of abode". A similar usage was that of Charles Darwin in his introduction to The Origin of Species, to refer to "Virginia squatters" (illegal settlers). [1]
Spaniards in Florida called them “Quáqueros,” a corruption of the English word “Quaker,” which the Spanish used to contemptuously refer to any Protestant. [2]
Other possible origins of the term "cracker" are linked to early Florida cattle herders (Florida crackers) that traditionally used whips to herd wild Spanish cattle. These cowboys were distinct from the Spanish vaqueros of Florida. The crack of the herders' whips could be heard for great distances when they were used to round cattle in pens and to keep the cows on a given track. Also, "cracker" has historically been used to refer to those engaged in the low paying job of cracking pecans and other nuts in Georgia and throughout the southeast U.S.
According to the 1911 edition of the Encyclopedia Britannica, "cracker" is a term of contempt for the "poor" or "mean whites," particularly of Georgia and Florida. Britannica notes that the term dates back to the American Revolution, and is derived from the "cracked corn" which formed their staple food. [3] (Note that in British English "mean" is also a term for poverty, with no malice implied.)
Historically the word suggested poor, white rural Americans with little formal education. Historians point out the term originally referred to the strong Scots-Irish of the back country (as opposed to the English of the seacoast). Thus a sociologist reported in 1926: "As the plantations expanded these freed men (formerly bond servants) were pushed further and further back upon the more and more sterile soil. They became 'pinelanders', 'corn-crackers', or 'crackers'." [Kephard Highlanders]
[edit] Folk etymology
There is also an apocryphal belief that the term dates back to slavery in the antebellum South. The popular folk etymology is based on slaver foremen using bullwhips to discipline African and African American slaves, and the sound of the whip being described as 'cracking the whip'. The foremen who cracked these whips are believed to have been known as 'crackers'."
I've had some discussions here in Holland with some folks from Suriname, one of out former colonies (and yours). Black people in Suriname (from slave ancestry) often refer to white people as "bakra", without thinking about what the word means. I tell them not to do it, as by using that slang word, they are in fact degrading themselves.
Bakra is short in Sranang Tongo (commonly known as Surinamese) for "basi van mi kra", which in turn is Surinamese for "boss of my soul". That's how they viewed the slavemasters. Clearly, by refering to somebody as the boss of your soul, you are putting yourself in a very, VERY low position...
Each one, teach one and all that...
