1893 - Thomas Edison received two U.S. patents. The first was for a "Cut Out for Incandescent Electric Lamps" and another for a "Stop Device" (No. 491,992-3). Also No. 492,150 for "Process of Coating Conductors for Incandescent Lamps."
... commonly abbreviated DRM, is an umbrella term for any of several arrangements by which the usage of copyrighted data by someone who has purchased a copy of it may b ...