How strong are the magnets that are used to keep a macbook screen closed? Obviously it isn't too strong to mess up the internal hard drive, but what about external hard drives? I am pretty sure that the magnets are located in the corners of the screen bezel, but I am not sure. Are there any magnets in the base of the computer itself? Is it ok to have an external laying right next to the computer? Sorry for all the questions, they just popped through my head. All answers appreciated!