why major number always 250 in device driver

[shaswat]

why kernel assigns 250 as a major number in device driver

Hi all,

I recently stated working on device driver development. Initially, I build a simple driver and application. The thing which I notice are that every time when I inserts my module, kernel assign a major number 250. I wants to know why always it assigns 250 ?? Other thing that I wants to know that I have generated my device file using command "mknod". What about if I want a create a permanent device file in my device memory that remains in it even after shutdown?

Any idea would be really appreciated.

 

[phoenix prasanna]

Re: why kernel assigns 250 as a major number in device driver

If you have not specified the Major number in register char device command while creating node it is set by default option in kernel.

 

[shaswat]

Re: why kernel assigns 250 as a major number in device driver

If you have not specified the Major number in register char device command while creating node it is set by default option in kernel.

240-254 is the range for local/experimental use. Why 250 exactly always?