Questions tagged [operating-system]

An operating system (OS) is a basic software whose role is to be an abstract layer between software requisitions for resources and the hardware available. The basic components of an operational system can be listed as:

• Boot loader

Although some may say it is not part of the OS, it's the starting point where the hardware after doing booting routines transfers the control to a small procedure that will bring up the entire system

• User interface

Can be graphical or text-based, is the central point of communication between the user and the OS

• Kernel

The core of the OS that manages all the resources of the hardware according to the requisitions. Kernels can be either a micro kernel or a monolithic kernel. Both types include the following functionality:

• Process management (scheduling, multitasking, pseudo-parallelism, and so on)
• Memory (and virtual memory) management
• Inter-process communications (IPC)
• Interrupt management
  
  

Monolithic kernels include these additional features:

• File system and disk access organization
• Device management (with the aid of device drivers, plug-and-play routines, dynamic modules, and so on)

These features are not included directly in a micro-kernel, but are instead implemented in tasks. One example of a fairly widely used micro-kernel is QNX. As well, many hypervisors are micro kernel designs. A major argument for micro-kernels is that their small size makes them easier to analyze and more secure.^Tanenbaum

Most well known operating systems are monolithic. In fact, the majority of commercial and Open source OS's are monolithic. Generally they allow faster hardware response.

Book : Operating System Concepts by Abraham Silberschatz

Recommended preliminary reading before posting a question: OSDev Wiki

See also: bootloader gui microkernel kernel hypervisor.