The term 'EARLY PC INTERFACE' can be summarized as a crossword solution with the word 'MSDOS' (5 letters). MSDOS stands for Microsoft Disk Operating System and was the first operating system released by Microsoft in 1981. It was the primary operating system used on IBM-compatible personal computers during the 1980s and early 1990s. MSDOS was an early PC interface that allowed users to interact with their computers.