Why Does Software Rot?
An interesting simile here is that software rots in the same way that Encyclopedias do.<p>(This is admittedly a fitting simile partly because the simile itself is being rotted by software like Wikipedia.)<p>In the world where new Encyclopedias (and Almanacs and Recipe Books) were printed and sold on an annual basis, the question was often why do we need &quot;this year&#x27;s Encyclopedia&quot; when the old one is still perfectly valid. Books in general decay pretty slowly and have a long shelf life, but the facts and the views in the world inside them are frozen and possibly. Changes from year to year of an Encyclopedia are somewhat hard to notice, but in Middle School in the 90s I recall having to compare articles from a tobacco yellowed Encyclopedia set from the 70s to trips to the same articles from very early predecessors of Wikipedia. The worlds contained in those two sorts of Encyclopedias were very interestingly diverging. The yellowed Encyclopedia&#x27;s facts were almost all still valid and &quot;worked&quot;, but there were things that didn&#x27;t hold up and lots of new facts that needed to be inserted in various places. If I were to edit an Encyclopedia, I&#x27;m not sure I would start from the version in that yellowed Encyclopedia if I could find a more recent set. Some of the predecessors to Wikipedia were direct descendants of that yellowed Encyclopedia and yet for various reasons historical and technical, Wikipedia itself did not inherit directly from that set in any meaningful way.<p>(It&#x27;s interesting to note too that the physical media of software to date has a much shorter shelf life than the pulp medium of books, tobacco-smoke-filled library aging included, so argument exists that software rots worse than Encyclopedias physically, at least.)