Unix System Organization

Unix is managed in three levels. On the upper most level resides the tools and applications.The second one is the Shell. The shell is called as the interpreter. because it translates whatever we type and transfers to the kernel.
On the other hand, the kernel is the heart of Unix. It interacts with the hardware.
The kernel has various functions. It manages files, carries out all the data transfer between the file system and the hardware, and also manages memory. The kernel program is stored in a file called unix and the shell program is stored in a file called 'sh'