What is the serial number of a partition of harddisk?

Question

While working with DOS,when I used the vol command the screen displayed the serial number of the drive,what actually is that serial number in terms of its need?

Answer 1

Source - Here

A volume serial number is a serial number assigned to a disk volume or tape volume. It originated in 1950s in mainframe computer operating systems. In OS/360 line it is human-configurable, has a maximum length of six characters, is in uppercase, must start with a letter, and identifies a volume to the system in unique manner. For example "SYSRES" is often used for a system residence volume.

In FAT and NTFS file systems, a volume serial number is a feature used to determine if a disk is present in a drive or not, and to detect if it was exchanged with another one. This identification system was created by Microsoft and IBM during their development of OS/2.

The FAT/NTFS serial number is a 32-bit number determined by the date on the current computer at the time of a disk's formatting. Previously, the method used to discern whether a disk was swapped was reading its volume label. However, it was not required to be unique or even non-empty. Many users had not given disks any name.

In extN and several other filesystems, the serial number is a 128-bit randomly generated UUID.

Answer 2

I find it helpful for persistence with removable devices in particular.

I have 2 apps that make use of that value.

One is a backup application that uses the serial in the path rather than the mountpoint, which helps keep rotations in line.

Another is a mountpoint reservation app that provides functionality for Windows similarly to that of the UUID syntax in linux's fstab mountpoint configuration.