HP-27s and direct solutions legend

[rprosperi]

(11-04-2018 08:13 PM)Vincent Weber Wrote:  The 27S is probably the most underrated calculator ever. It was sadly discontinued pretty early (< 1993). One could argue that the 19BII was a good replacement for it, with all its functions (except precedence and base conversions) and more... But the 27S (1) has a much smaller footprint (truly pocketable) and (2) has the scientific fucntions on keyboard, not burried in the MATH menu...

And its "programming" model is very unique. The flexibility of the solver allows you to do much of what keystroke programming can do, but in a much more user-friendly manner (you only write equations, not programs): you get conditionals (IF), loops (sigma) with the possibility of emulating undefinite loops, statements (L and G functions)... It is similar to Excel formulas in a way. If only it had the ability to define functions (to be reused) and to set values in list (for indirect addressing) it would be as powerful as a 42S, you could emulate matrices ! It does not have integration, but adding it as a solver formula is easy.

I guess it was too odd as a scientific calculator, and that the concept of a "do everything" (scientific + business) calculator never took off... A pity, because the 27S is really loved by those who know its outstanding capabilities.

I totally agree, the 27S is a great machine, and is the only Algebraic HP machine I will use. If only HP had released the 27SII with RPN (like the 17BII and 19BII), it would have gone on to huge success and very widespread use, but HP probably feared it would seriously impact sales of the 48SX, introduced around the same time-frame. And that likely was correct reasoning; I think a lot of folks would have stayed with RPN.