A volume serial number is created based on a fairly complex combination of the year, hour, month, second, and hundredth of a second that the drive was formatted.
Since volume serial numbers are not generated at random and without knowledge of the volume serial numbers on other drives in the computer, there's a chance that two drives on the same computer could end up having the same volume serial number. However, the chance is infinitesimally small and isn't considered a concern.
Because the volume serial number is generated during the format, it will change each time the drive is formatted. There are some methods of changing the volume serial number manually but the ability to do so is not included within Windows itself.
Here are some common things you might do related to volume serial numbers:
- Find the Volume Serial Number of a Drive in Windows
- Find the Volume Serial Number of a Drive From the Command Prompt