Friday, July 08, 2005

Types of kernel


Since, I am running out of time today, I will explain you the types of kernel shortly. Basically, there are three types of kernel:

  • Monolithic Kernel
  • Micro Kernel
  • ExoKernel

Monolithic:
As the name itself suggests, the kernel has every services like, FS Management, MM, Process Management, etc. in the kernel space. It does not run as a seperate process. So, as you guess, there is no context switching, when you ask for a service. But, the probability of a monolithic kernel getting struck is more. Because, if there is a bug in the kernel itself, nothing can rescue it. Linux and Windows are good examples of Monolithic kernel. Linux, being a monolithic kernel, you can insert modules into the kernel dynamically using insmod command.

Micro Kernel:
Micro kernel runs all the services as a daemon in the user space. So, if a problem occurs in any of the service, the kernel will be able to decide what to do next. But, you pay-off the time to switch to a service in this type of kernel. Micro kernels are some what difficult to design and build than the monolithic kernel. There are always a discussion over the internet, talking about the advantage and disadvantages of monolithic and micro kernel.


Exo Kernel:
Exo kernel is not yet stabilized. It's under design and research. The user mode processes running in this type of kernel has the ability to access kernel resources like process tables, etc directly.

4 comments:

ask said...

there is one more type:
Hybrid kernels are part of the operating systems such as Microsoft Windows NT, 2000 and XP. DragonFly BSD etc. These types of kernels are extensions of microkernels with some properties of monolithic kernels. Unlike monolithic kernels, these types of kernels are unable to load modules at runtime on their own.

Anonymous said...

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Anonymous said...

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Anonymous said...

this is bullshit