Mention the words “DRM” and “Sony” in the same sentence and most people will have some bad memory of the company’s use of a rootkit on music CDs a few years ago.While Sony may have learned its lesson when it comes to rootkits, DRM is still a security measure it has yet to fully grasp. If DRM is going to be used to protect content, it should do so transparently and without affecting a legal user in any way. That is not the case it seems with the DRM used on DVDs containing the recently released Angelina Jolie movie Salt.Apparently, the DRM makes the disc unplayable on certain DVD players. It’s so bad that in order to eject the disc you have to time your press of the disc eject button perfectly.Chris Swan experienced this first hand when trying to play the DVD on a Kiss DP-600 DVD player. The disc spun up in the player, starts to play, but then the player crashes and switches itself off. Restarting the machine results in the same sequence of events and requires the timed push of the eject button.We don’t know how many different models of DVD player this affects, but if you have experienced the same problem list the model below as a warning to others.Read more at Chris Swan’s WeblogMatthew’s OpinionI think the people who make the decisions to use this DRM on discs must live in a bubble, or really don’t care that it may break some DVD players. Even worse are those companies producing this DRM knowing that it will not work with all DVD players.As is always the case, the cost of using this DRM, and the inconvenience caused to consumers by it, is a complete waste of everyone’s time and money as the movie is already widely available on file-sharing networks DRM-free.DRM does not work, it never has, and probably never will unless it is combined with some other security measure e.g. Steam’s method of serving games. Until such a method exists for movies, the publishers will continue to waste money on DRM and consumers will continue to be frustrated by it.