Remember "2 bits; 4 bits; 6 bits; a dollar"?

Where did those terms come from? The old silver Mexican and Spanish pieces of eight dollar that used to be cut up into fractions of a dollar. 2 bits = 1/4 or .25¢. 4 bits = 1/2 or .50¢. 6 bits = 3/4 or .75¢. 8 bits ... or 8/8ths = $1.