The word processor was a stand-alone office machine in the 1960s, combining the keyboard text-entry and printing functions of an electric typewriter with a recording unit, either tape or floppy disk (as used by the Wang machine) with a simple dedicated computer processor for the editing of text. Although features and designs varied among manufacturers and models, and new features were added as technology advanced, the first word processors typically featured a monochrome display and the ability to save documents on memory cards or diskettes. Later models introduced innovations such as spell-checking programs, and improved formatting options.