Why not 128? Why not 1456? A certain size byte value will always take up exactly the same space regardless if it is at 0 or it's maximum value. The bytes that recorded items were probably two seperate bytes, one to record the type of item, the other the amount. The amount is probably a 7-bit integer, so any value between 0 and 127 would be applicable. As rubah says, it's probably because it's a nice round number. Not in technical terms, but certainly in human terms.