I don’t know how, but my 15-year-old HP 20S calculator just “died” a week ago. As I am looking for a replacement, I learned that the legendary keyboard on HP calculators is now history, at least in the scientific series. Sigh…
When I was a high school student in Hong Kong, I had a couple Casio, a Sharp and I finally landed on the HP 20S because of its tactile feedback keyboard. In an exam, having tactile feedback takes away the “did I push that key hard enough?” guessing. I guess someone may say that 20S is not RPN and so it is not cool. But then Hong Kong has its own list of approved calculators and the 20S is the already most advanced HP calculator on the list. Basically we disallow any calculator that can graph or store alphabets.
And now I know why the other companies don’t have a similar keyboard. As Google just told me, HP holds a patent on it.
No wonder a used HP 32SII can sell for \$229.
Update: I must add that the HP 33S (the 32SII replacement) does have tactile feedback, but according to reviews, it is not reliable.
