There used to be other backends in addition to C: Java, CSharp, and Javascript but those suffered from bitrot and have been removed.

Refactoring is a means of addressing the problem of software rot. It is described as the process of rewriting existing code to improve its structure without affecting its external behaviour.

Suppose an administrator creates a forum using open source forum software, and then heavily modifies it by adding new features and options. This process requires extensive modifications to existing code and deviation from the original functionality of that software.

cannot be run on any modern day computer or computer simulator, as it was developed during the days when LISP and PLANNER were still in development stage, and thus uses non-standard macros and software libraries which do not exist anymore

Software that is not currently being used gradually becomes unusable as the remainder of the application changes.

will eventually lead to software becoming faulty, unusable, or in need of upgrade.

Digital technology may contain no moving parts but it still, somehow, gets worn, splintered and corroded. It rots. It decays. The rot, though, is mostly invisible (and un-smellable). Still, one day, the thing is broken.