The Serial Copy Management System or SCMS was created when the digital audio tape (DAT) was invented, in order to prevent DAT recorders from making second-generation or serial copies. SCMS sets a "copy" bit in all copies, which prevents anyone from making further copies of those first copies. It does not, however, limit the number of first-generation copies made from a master.
SCMS was an early form of digital rights management (DRM).
