* Description: Knowledge of Operating System kernell and shell
* Compatiablity: RDBMS 11g, 12c
* Date: 09:39 PM EST, 04/12/2017

<1> Kernel:
     |__ A program which controls all other programs on the computer. When the computer starts, it goes through some initialization (booting) function, such as checking memory. 
         It is responsible for assigning and unassigning memory space which allows software to run.
         It provides services so programs can request the use of the network card, the disk or other piece of hardware.
         (the kernel forwards the request to special programs called device drivers which control the hardware), 
         manages the file system and sets interrupts for the CPU to enable multitasking. 
         Many kernels are also responsible for ensuring that faulty programs do not interfere with the operation of others, 
         by denying access to memory that has not been allocated to them and restricting the amount of CPU time they can consume.

<2> Shell - Command Interpreter:
     |__ Some operating systems include the command interpreter in the kernel. Others, such as Windows XP and UNIX, treat the command interpreter as a special 
         program that is rmming when a job is initiated or when a user first logs on (on interactive systems). On systems with multiple command interpreters to
         choose from, the interpreters are known as SHELL.

     |__ http://emeralit.com/wiki/repo/file/FILE_03_OPERATING_SYSTEM_TURORIAL.pdf