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3:58:36
beach
I recently saw some very real evidence of the result of Kahneman as reported in his book "Thinking, fast and slow", i.e. that the fast module is lousy with things like orders of magnitude and statistics, and the slow module is lazy so it tends to believe the fast module. The evidence I saw makes me very convinced that a large number of wrong decisions are made with respect to software development.
3:58:44
beach
In this case, I mentioned that I plan to track source information in SICL by keeping a string containing the text of each source file in memory with the code, and I got a pretty violent reaction.
3:58:46
beach
After some verification, it turns out that the entire source code for the Lisp machine is around 50MB, which represents 20 cents of RAM. For the SICL source code, it's 6.4MB or around 3 cents. The fast module had obviously estimated several orders of magnitude more and the fast module didn't bother to check.
4:01:12
beach
The advantages of keeping the source code with the executable code is of course that, even if the source file was not delivered or installed, or if it was modified a posteriori, then I can still have precise error reporting with respect to source location.
4:03:16
beach
I am intimately convinced that many wrong decisions about what optimizations to implement are based on a hunch delivered by the fast module, and that if the slow module had bothered to check, it might turn out that the potential gain is very small and that it would be better to spend that energy on more profitable work.
4:05:39
beach
Hmm, I might get a chapter in my book about the sorry state of the software industry out of this kind of material.