Some Basic Concepts and Terms regarding Operating System

        Here are some basic terms and concepts regarding operating systems, and computer hardware that we will need to study actual operating systems. Without knowing these concepts it will be sort of difficult to start.
First.I was thinking to explain these terms wherever occurred, but this would have made the blog posts a little lengthy and out of track.
So I decided to put them in the very beginning.
These definitions are not 100% formal, I've kept them on a very introductory level, they'll be explained wherever required.

• Resources: A resource or a computer resource is any physical or virtual component of the computer system. Every device connected externally to a computer system is a resource. Every internal system component is a resource as well. That includes the processor (CPU), RAM ("memory" in nerd -peak), I/O devices and so on.
  Virtual system resources include virtual memory, files-systems, and so on.
• Process: An informal, most basic definition is that "a program in execution is process." A computer program is just a collections of instructions for a computer. When a computer starts to obey these instructions, that is, "starts to execute" this program, it is called as process, that is it.
• Devices: A device is a piece of hardware connected internally or externally to main computer system. (I don't know what it is called when it is not connected to the computer, every man has his flaws...) Hard disks, disc drives (CD/DVD drives), key-boards, and video monitors are typical devices to be found.
• Device Controller: In simple language, device controller is part of the motherboard, it allows the motherboard to use the device. Technically, devices have a special electronic interface, called as device controller, which helps to connect a device or a group of similar devices to a computer system. Device controllers act like a glue between devices and main computer system. Just like the gluon inside a proton or neutron, who is responsible for sticking the quarks together.
• Device Driver: (Not to be confused with device controller) This is a program which helps the software to use the hardware. (Device controller helps motherboard, device driver helps the software.) Device drivers are hardware-dependent and operating-system-specific.
• BIOS: The first task of Basic Input/Output System is to identify standard system devices such as the video display card, keyboard and mouse, hard disk drive, optical disc drive and other standard hardware. After Accomplishing this task, BIOS is responsible for loading the operating system. BIOS program is stored on a non-volatile ROM chip, present on the motherboard.Usually this ROM is made of CMOS chip.
• Kernel: Kernel is a program (actually set of programs or "module" in nerd-speak.), that is always running at all time on computer (unless it is turned off obviously, as mentioned previously.) or atleast  is always present in the main memory (RAM).
      In some cases (like Linux), the entire OS is created as one monolithic entity and this entire monolithic entity is called as kernel.
• Services: One of the major tasks of operating system is to provide an environment for the execution of program(s). The OS provides some "services" to make the programming task easier. These services are provided provided not just to the user, but to the programs as well.
      The services provided may differ from OS to OS. But still, these services can be categorized according to their functionalities.
      The most familiar services to a common user are user interface and file manipulation. (yes, this might come as surprise, but user interface is a service.)
      In current days, a graphical user interface (GUI) is the most commonly used interface, other interface being command line interface also known as line based or text based interface.
      Talking about file manipulation, a user needs to read and write files, he also needs to create and delete them, programs as well, needs to perform same tasks regarding files. It is "file system"'s job to provide these services.
• Utility Programs: The most common and informal definition is, the programs which help the OS to keep on working, but however, this definition is not completely correct.
      Utility programs are not the part of the OS kernel, but work closely with the kernel to provide the ease of use or access to the system information.