It might have had advertisements that listed the 15C and the 16C and the 11C and so on, but never for the 15C in its own right except for one in Japanese. Well, HP never produced an advertisement for the 15C in its own right in any Western language.

We could probably look at the manuals and find out exactly when it appeared. KAHAN: I think it was 1982, give or take. HAIGH: What year did the calculator appear? MIT, for example, for a couple of years was telling its freshmen that they should buy the calculator, and it had a special deal with HP that would get them involved in a somewhat lower price. … The marketing people had a third of my number, and Harms ended up with the production line producing half of my target number, and then these calculators were disappearing off the shelves as fast as they could be supplied. They wanted a third of my figure, and Dennis Harms did half again what they wanted, and that’s what they were doing. KAHAN: “The HP 12C was successful enough that they were willing to take my advice about building the 15C, but not take my advice about how many to build. William Kahan regarding the quantity of HP-15C that he estimated HP could sell per year: Tangentially related to the quantity of HP-15C units that HP produced.įrom Dr. Could it be that the nnnnn component of the 15C serial number is not the number produced in a week but rather the sequential number produced in the year? This seems to me to be an implausible number even without considering the other models that HP was producing at the same time. 80,000 a week for 50 weeks a year for 7 years (1982 to 1989) is 28 million with an additional 14 million or more from Brazil (assuming 40,000 per week given the Brazilian serial number 38,564) giving an estimated total of 42 million. On HP 15Cs made in the USA serial numbers appear on the top edge in the form yywwAnnnnn where the number yy + 60 denotes the year ww denotes the week produced A, the USA (B for Brasil) and nnnnn the sequential number of the calculator produced in that particular week.Ĭonsider the following serial numbers of HP 15C calculators:Īlthough the sample is small we can deduce from calculator number 79,855 that at least 80,000 were produced a week in the USA in 1985.

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