Digital data storage on microfilm is a highly attractive technology for archiving of digital data. Its estimated storage lifetime of up to 500 years outperforms conventional storage media such as CDs, DVDs, hard drives, or magnetic tapes. Today, migration is widely used as a solution for long-term data storage but unfortunately also requires costly and time-consuming migration steps. Microfilm offers migration-free data storage and also further advantages as the uncomplicated technology of reading devices and hybrid storage of analog and digital data on the same medium. Due to its write once read many character, it is inherently forgery-proof and safe against virus attacks. This article describes the underlying technology of digital data storage on microfilm, including laser recording, error correction codes, and important system parameters. Possible storage capacities are pointed out and potential applications as well as future developments are described.