“While everyone knows that computers are binary, not many people
understand the numbering systems that represent the binary numbers
stored in computers, or the notational conventions used for
displaying this information.”
“This may be a teensy bit painful, but I need to cover it to
further explain setting file modes. If you understand binary
numbering, feel free to skip ahead.”
“An odometer in an automobile measures mileage by wheels that
rotate through the digits 0 to 9. Each time a wheel completes a
revolution from 0 through 9 and back to 0, it trips the wheel to
its left up one position. When that wheel reaches 9 and is tripped
over to 0, it increments the next wheel to its left.”
“Now imagine that each wheel in your odometer only had the
digits 0 and 1. The first wheel would increment from 0 to 1 and
back to 0 again. As it rotated back to 0, it would trip the wheel
to the left over to 1. Wheel 1 would again spin through 1 and back
to 0, and this time it would trip wheel 2 over to 0. This would
trip wheel 3 over to 1. The following illustrates the sequence of
positions for our wheels. The wheel positions are numbered down the
left-hand side so that position 0 is 0000, position 1 is 0001,
position 2 is 0010, and so on.”