Bit Rot - Problems With Software

Problems With Software

The term "bit rot" is often used to refer to dormant code rot, i.e. the fact that dormant (unused or little-used) code gradually decays in correctness as a result of interface changes in active code that is called from the dormant code.

A program may run correctly for years with no problem, then malfunction for no apparent reason. Programmers often jokingly attribute the failure to bit rot. Such an effect may be due to a memory leak or other non-obvious software bugs. Often, although there is no obvious change in the program's operating environment, a subtle difference has occurred that is triggering a latent software error. The error in the software may also originate by human operation which allows the construction or derivation of false-positive behavior to occur within the code. Many if not all operating systems tend to lose stability when left running for long periods, which is why they must be restarted occasionally to remove resident errors that have built up due to software errors.

The term is also used to describe the slowing of performance of a PC over time from continued use. One cause of this is installing software or software components that run when the user logs in, causing a noticeable delay in boot time. Also, the addition of programs and data on the computer can make operations and searching slower, and sometimes when programs are uninstalled they aren't removed completely. Additionally, fragmentation can slow performance. Normally, unused data (such as a text file containing some notes) does not impede performance of a PC (with the exception of software that, for example, indexes files on a disk to make file searching faster).