On Tue, 18 Feb 2014, Brian Reay wrote:

On 18/02/14 15:21, Phi wrote:
I paid about £180 for an HP35 in 1973, this calculator used reverse
polish notation (no equals key).
That seems cheap for an HP at the time. As I recall, that was the launch
price of the Sinclair, although it soon dropped.

The Sinclair was also RPN, as were the early Texas calculators I think.
Sinclair lacked the "Enter" button, using the + key its place.

I don't remember the TI calculators having RPN. I remember them as being
more reasonably priced versions of "electronic slide rules", which was
what they called them originally.

It's odd to look back now. I think that HP35 that a fellow ham got in
1972 or maybe 73 (a group buy at his place of employment) was the first
pocket calculator I ever saw close up. So many functions, yet so few
compared to what you can get on a $10 calculator today

I don't know what the first TI scientific calculator cost, but it was less
than the HP by far, and soon you could get one in the $50 range, and then
$30 range, which is when I got my TI-30.

Such a big change, a sudden surge in articles in the ham magazines showing
equations, suddenly you could actually work things out without needing
much math skill.

I think it was the National scientific calculator that had RPN, coming
later but also being quite cheap.

For the 'everyday' user, RPN was not popular and calculators offering,
almost, algebraic, entry became more popular. I think the first calculator to
offer true algebraic entry (ie following BODMAS/BIDMAS convention) was Texas.
Even today some cheap calculators don't follow the convention. One of the
many things I warn pupils of when I teach calculator use.

That's interesting. I look at the cheapest of the cheap scientific
calculators, and the functions are at least the same as my TI-30 from
about 1977. I assume the calculators have gotten so cheap because the
work was done long ago, buying old technology to implement cheap today.

Michael