[MATHEDCC] HP Calculators

Phil Mahler (mahlerp@admin.middlesex.cc.ma.us)
Sat, 20 Sep 1997 07:23:58 EST5EDT4,M4.1.0,M10.5.0

>At 05:31 PM 9/18/97 EST5EDT4,M4.1., Phil Mahler wrote:
>
>>I was educated with no more than the slide rule, which course was probably
>>demonized when it was introduced in the 19th century. But I can remember
>when I
>>paid $500 for a programmable HP-25. All of 49 steps! I stayed up all night and
>>wrote a program which would factor integers.
>
>Your memory is faulty. No Hewlett-Packard 20-series calculator ever cost
>half that much. The hp 65 cost $800 in 1974 (maybe 75). The hp 67 and 97
>also cost over $500 a few years later. The subsequent top-of-the-line hp
>calculators cost significantly less than $500. The current top-of-the-line
>hp calculator is the hp48G, which is often discounted to less than $100, and
>worth every penny.
>

Can't argue that my memory is faulty. It may have been an HP-45. And my wife
says it was more like $200. Though I'm pretty sure it started out around $600
and I bought it when the price came down. This would be in 1975 or so. I was
a grad student at the University of Florida, and one of our profs (math) would
wear his in it's beautiful carrying case on his belt.

Though I'm pretty sure about the 49 programmable steps. A real challenge to
write a meaningful program in that few steps, when the addition of two numbers,
for example, used up 3 steps (a, b, +).

But I really did say up all night programming it - I was a real techno-junkie,
which has never changed through "trash 80s" and Apple IIs, IBM 360s using
computer cards, whatever...

I also like HPs very much, and have owned several since, though not the latest
models with symbolic capabilities. I believe that the convergence of calculator
and computer technology is in palm tops with qwerty keyboards and large screens
(and 2^15-1 colors etc.!) so I lean more towards the 92 for mathematics.

I always liked the RPN (reverse Polish notation) notation that the HPs used - on a
complicated expression it is much more efficient than figuring out where to put
parentheses as needed on an "algebraic logic" calculator... IF you understand the
order of operations convention.

In computer science I used to teach data structures students how to convert
an algebraic expression in something like FORTRAN or Pascal to RPN, because
in fact that's the form needed inside the computer. It was a nice application
of recursion and stacks. And occasionally a student would go out and buy an
HP just because RPN applealed to them so much.

All this to apologize for a faulty memory and dispel any impression that I don't
like Hewlett Packard calculators.

Phil Mahler
Middlesex CC
Bedford, MA
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