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Re: [vsnet-chat 5989] Re: [vsnet-campaign-ccd-discussion 30] (fwd) Re: [AAVSO-DIS] CCD-V Vs visual observations > Whenever one assumes blindly that all the softwares does what > one thinks they do, then the person is one step closer to shooting > his/her own feet. So don't assume that there is such a thing as > the "most unreliable" software. More often, many "software" problems > are due to user errors. User errors are a serious cause of the problem. Even if the software gives correct results, an error in identification of the variable star will not be recovered even by careful programming of the software. Even disregarding such a cause of errors, some software more frequently gives incorrect results than others. If there is a JD to HJD (heliocentric conversion) error, most users will not be aware of the error until he or she compares the results with other software, or finds a deviation from the ephemeris -- but such lucky things rarely occur, and most of the problems are more subtle, or more difficult to identify. If some program produces such difficult-to-understand problems more frequently than others, it would not be a bad approximation that such a program would produce more frequent problem in other circumstances. The problem in software is that it is becoming incresingly difficult to fix bugs. It is a good approximation (from a view of information technology) that the frequency of bugs is proportional to (complexity)^N, where N is larger than unity. This is well-known that this scaling law determines the maximum reliable size of software, at which the introduction of new bugs (proportional to (complexity)^N) becomes comparable to removal of bugs (proportional to ~complexity or less). The present complexity of software already exceeds that of user's ability to regulate the occurence of bugs. Bugs are increasing more rapidly than users can identify them. Think of the earliest bug in Pentium. That was a very simple bug (incorrect arithmetric), but it took a long time before the problem was recognized. > In short, everyone should have some simple way to test and see if > your "software" works the way you expect it to be. If not, ask > developers about it. So it is virtually impossible to expect users to make such tests. Even if a user would have motivation to make tests, either most the information of the software is insufficient or the user lacks the necessary skills. Even in the luckiest cases when the problems are identified, developers are usually very busy and are usually reluctant to fix bugs in already released software, and are usually more rushed to continue developing and releasing new software. Regards, Taichi Kato
Return to the Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
