As its name implies, the kernel is at the core of each UNIX system.
Basically, the kernel is a large program that is loaded in whenever the system is started up - referred to as a boot of the system, and it controls the allocation of hardware resources from that point forward.
The kernel knows what hardware resources are available (like the processor(s), the on-board memory, the disk drives, network interfaces, etc.), and it has the necessary programs to talk to all the devices connected to it. It manages the entire resources of the system, presenting them to you and every other user as a coherent system.
You do not need to know anything about the kernel in order to use a UNIX system. This information is provided for your information only.
Location of the kernel file; the root directory contains both the boot program and the file containing the kernel for the system. The name of this kernel file varies from one manufacturer's machine to another. You can search for it as;
$ls -l /boot/vmlinuz*
-rw-r-r- 1 root root 2359087 Sep 22 00:20 vmlinuz-2.4.26
In this example; Linux kernel is given, but a similar name can be found for the other variants of UNIX.
