Dual mode operation in Operating System Easy to understand

If you are searching for what is Dual mode operation in Operating System then you are at the right place so let’s get started.


why we need to use mode operations in operating system?

First we need to understand that why we need to use mode operations so let’s understand suppose there are two programs executing at a time and one programs occur an error so that one programs affects to second programs so that’s why we used mode operations.

In the hardware level, Instructions are executed in two different modes. (Dual mode operations) So let’s see that two dual modes.

  • User Mode
  • Kernel Mode


User mode In Operating System

Let’s understand user mode with example suppose I opening one text editor and start writing code there in that code I need to open one file from computer and I want to write something in that file at that time user mode convert into the kernel mode to fulfill the requirement to fetch that text file.


Kernel mode In Operating System

So here one question arise that why we need kernel mod because suppose we need fetch some data from Hard disk. To fetch data we need to use kernel only because user mode can’t fetch data, if we want to fetch the data from Hard disk we need to use kernel mod.

Let’s understand with the help of diagram. Here I present you one diagram see this and try to understand.

Dual mode operation

So hope you understand the diagram if no then I explain you what is happening their here.

The first thing written there is user process executing which means suppose I open one text editor to write one simple code of open one file from system and write something inside that file.

Suppose think I wrote that code and stat execute that code so the first thing is to fetch the file from hard disk and that only done by kernel mode so now operating system goes into kernel mode and fetch the file from hard disk and make changes there and come back to user mode.

And here one more important thing is when user using a user mode the mode bit is 1 and when user goes to kernel mode the mode bit is 0.


So I hope you understand what is Dual mode operations in operating system so if you get the answer what you want then share this article to your friends and if you have any question the feel free to ask me in comment section and if you want this type of information then do email subscription for daily update directly to your inbox thank you for reading this article.


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Unknown said…
Nice explanation 👍