Emulator ROM image file (8-bit Sega Master System)
SMS is a file extension for a read-only memory (ROM) file extracted from a Sega Master System cartridge. SMS stands for Sega Master System. SMS files contain a copy of a Master System game, which can be used with a Master System emulator. SMS files allow the play of Master System games on other operating systems, including Windows. SMS files are created with a flash cart and software proprietary to the flash cart used.
Learn more about .SMS files:
Visit the Sega web page.
Read more about Emulators at ITKnowledgeExchange.com.