(Second question.) I have a problem with lecture 31. I did everything, that was...

> Programmable Interrupt Controller Implementation

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Question by Svyatoslav Matveenko

(Second question.) I have a problem with lecture 31. I did everything, that was shown in the lecture. But, for some reason, my QEMU writes a start message, and then it immediately writes "keyboard pressed", without actual keypress. I tried to copy your code from the GitHub with the only change of variables names. (e.g. int21h to INT21H in all files), but the problem remains. Can there be any hardware or software features, that causes this issue? Or am I doing something wrong? (I'm using Linux)

Answered by Daniel McCarthy

Hello,
No their wouldnt be an issue with hardware as your using the same emulated environment as in the course. You have made a mistake with your code, it would be impossible for me to help without manually debugging your code base.

The best thing to do at this point is to download the source code at this point in time and run it as a separate project. All will work fine, now compare the differences until you figure out what you did wrong.

Alternatively you can attach GDB and manually debug your code base yourself, this is shown to you at some point in the course during your progress . Kernel development is difficult and part of the skillset is learning to debug kernels, see this mistake you have done as a blessing, you will now learn the skills to solve it using a debugger. Doing kernel debugging is a great skillset to have.

If you have any questions about how to debug your code with tools such as GDB just let me know and I will further assist.

Thanks,
Dan

Answered By Instructor