code. Differences between documentation and product. Implications The amount and type of damage a software bug may cause naturally affects decision-making, processes and policy regarding software quality. In applications such as human spaceflight, aviation, nuclear power, health care, public transport or automotive safety, since software flaws have the potential to cause human injury or even death, such software will have far more scrutiny and quality control than, for example, an online shopping website. In applications such as banking, where software flaws have the potential to cause serious financial damage to a bank or its customers, quality control is also more important than, say, a photo editing application. Other than the damage caused by bugs, some of their cost is due to the effort invested in fixing them. In 1978, Lientz et al. showed that the median of projects invest 17 percent of the development effort in bug fixing. In 2020, research on GitHub repositories showed the median is 20%. Residual bugs in delivered product In 1994, NASA's Goddard Space Flight Center managed to reduce their average number of errors from 4.5 per 1000 lines of code (SLOC) down to 1 per 1000 SLOC. Another study in 1990 reported that exceptionally good software development processes can achieve deployment failure rates as low as 0.1 per 1000 SLOC. This figure is iterated in literature such as Code Complete by Steve McConnell, and the NASA study on Flight Software Complexity. Some projects even attained zero defects: the firmware in the IBM Wheelwriter typewriter which consists of 63,000 SLOC, and the Space Shuttle software with 500,000 SLOC. Well-known bugs A number of software bugs have become well-known, usually due to their severity: examples include various space and military aircraft crashes. Possibly the most famous bug is the Year 2000 problem or Y2K bug, which caused many programs written long before the transition from 19xx to 20xx dates to malfunction, for example treating a date such as "25 Dec 04" as being in 1904, displaying "19100" instead of "2000", and so on. A huge effort at the end of the 20th century resolved the most severe problems, and there were no major consequences. The 2012 stock trading disruption involved one such incompatibility between the old API and a new API. In popular culture In both the 1968 novel 2001: A Space Odyssey and the corresponding 1968 film 2001: A Space Odyssey, a spaceship's onboard computer,