I'm a newbie in the Linux environment, and I came a cross two concepts, the vmlinuz and initrd.
What I understood that initrd determines which kernel-modules need to be loaded to support the current hardware, and will load them, and also, to make the loading of Kernel faster.
So how does it solve that? How does it know the modules needed by my laptop hardware?
For example, if I installed Ubuntu on my laptop which doesn't contain a finger print device, and the same Ubuntu version on another laptop with a fingerprint device, does the initrd differ?
If it differs, so every time I add a new Kernel module the initrd would be upadted?
initrd does not contains all kernel modules. It contains required modules to start OS from some partition. Please look on it
Your finger print device will be initialized later, from the disk.
If your module should be initialized early, you should rebuild your initrd image.