Postman Sort is probably the newest linear order sorting algorithm for fixed domain sets in use today. It's developers claim that it is also the fastest such algorithm.
The algorithm works by sorting the numbers from their most significant digit to their least significant digit. Significant gain in speed is achieved by sorting the numbers on more than one digit at a time (the actual number is decided based on the size of the computer's memory). The process is also considerably speeded up by using some knowledge of the range in which the numbers lie, for example the fact that digits of octal numbers lie in the range 0 to 7.
For this visual demonstration we have sorted randomly input 9 digit binary numbers, using 3 digits at a time (The use of binary numbers enhances the clarity of the visual representation considerably).