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Hello all,

What was the reason that the stack roll operations were f- and g- shifted operations on the 34C when, on all the other Spice models, even the 37E and 38E/C, Rv was a primary key?

What was the reason that pi was a primary key on the HP-35 and shifted on all other handheld HP calculators?

My guess would be that, since the 35 had no shift key, to add pi as a shifted operation would detract from the goal of the 35's simple design and consistency of use.

Another thought is that keeping pi as a primary key is in line with grouping pi as a number entry key.

Edited: 23 Aug 2013, 5:43 p.m.

As far as I see on the pictures of the 37 & 38 models in the main exhibit hall the Rv function was also shifted there, so it was just the 31, 32 & 33 models where Rv was attainable without prefix...
I guess that the huge amount of functions on the 34C (which also brought the necessity of a third prefix key) was the main reason for putting the Rv & R^ function on "prefixed". It's just an assumption...
However, sometimes the need for pressing the g key for access of the Rv function annoys me, too, as it's an important function. On the 15C it was also possible to have Rv as primary function, even though this calculator offered an extended range of functions compared to the 34C with just two prefix keys...

Actually the same situation for the Sigma+ function on the 34C...

Thanks for correcting my fuzzy memory. Not certain why I didn't look here to see the pics of the 37 & 38. In any case, thanks for the memory fix.

You're welcome, Matt... ;-)

In short, there was no need for pi or any other function to be a shifted key because the HP-35 had so few functions that a shift key was not necessary at all (except for "arc", which was not exactly a shift key). As the number of functions increased one, two or even three shift keys were added to the keyboard. When calculators became programmable, the demand for primary function keys grew (R/S, A and B, on the HP-34C, for instance, would make no sense as shifted keys) and the less import Rv became a shifted function (it is shifted even on the HP-38C)

Thanks for that 'shift' of my thinking towards another direction. Your insights are quite helpful.