Dear Raghu,
Thank you very much for your reply. my error logging will be indeed based on flags and no new error will be added unless the last error situation has been removed. The system should control many steppers and DC motors and also has thermal control so potentially there are different sources of error. Actually I should implement error handling for different reasons (to run emergency codes for each error situation, informing user that something is wrong with the system and system can’t process his/her commands). so logging error was very easy for me just adding a few lines and a few variables and of course a flash. It doesn’t impose computational overload or extra code space.

Thank you very much indeed

PS: And please excuse my carelessness to post the reply to our friend kai to you