Casio’s blunder? Or not?

[Matt Agajanian]

Hi. Too easy that the little buggy calculator mentioned in the article was the HP-35 (that nasty ln 2.02 rascal). The later point that William Kahan found the HP-27 glitch and the calc was delayed raises the question—if the 27 was in the hands of an outside user who then found the financial glitch, why wasn’t the 35 given the same testing or an outsider willing to test the 35 before it went to market? Or was the 35 tested and used by an outsider before it was commercially available?