It's all about IP addresses!
The Arrowhead Systems website has one of the Internet's version 4 32bit numbers. It's 3,562,622,985 which is 11010100010110010101000000001001 in binary.
You don't need me to tell you that it's not easy to remenber! So to help make it easier we divide the 32 bit number in to 4 parts of 8 bits each and we put a . (dot) in between each part.
| 11010100 |
which in decimal is |
212 |
| 01011001 |
which in decimal is |
89 |
| 01010000 |
which in decimal is |
80 |
| 00001001 |
which in decimal is |
9 |
We end up with a number that you might be able to remember, our IP Address of 212.89.80.9
Now it was a good job that the Internet was just for scientists and academics in the late 80's, as these numbers aren't that much easier to remember either. The system of copying a master hosts file with all the machine names available on the Internet was cumbersome, so the DNS system was developed.