Editing Reproducibility (section)

==The "out-of-date" pitfall==

Let us presume a reproducible experiment was set up and verified, then archived to disk... is that all?

No. Software dependencies and platforms change in time. Each change is incremental, but overall they add up. An archived experiment will not run a few years later, when libraries are different, versions of compilers/interpreters are different, etc. The only way to archive an experiment statically, "maintenance-free" is to conserve the actual physical machine it was run on. Nothing less will do: even archiving an image of the whole disk does not help, as old OSs will lack drivers for new hardware. The solution is to re-run the experiment every time something changed in the system, from a bug fix in the source code of the experiment's tools to a new version of a library called by a dependency of a dependency. The experiments function as regression tests.