* Use a low level language already proven durable over decades: COBOL, Fortran * Minimize your footprint and test space in your application by eliminating feat

* Use a low level language already proven durable over decades: COBOL, Fortran * Minimize your footprint and test space in your application by eliminating features and options. * Eliminate use of external dependencies. That means abandoning certain utilities and writing your own as necessary. * Couple your application tightly to a given piece of hardware, like a very primitive RaspPi or some small hardware controller. * Provide documentation. Keep it precise yet small, like a wrist watch instruction manual. * Carefully consider your approach to data storage, if necessary. This can be a database or a file system or something else. Keep it primitive. Speed and cleverness are not important when the primary goal is archival. * Consider the physical and chemical nature of the hardware. Metals degrade over time and plastic becomes brittle. A purely glass, crystal, or other silicon based media could last many thousands of years in isolation.