HP15c CE: 8x8 equation system

[Valentin Albillo]

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Hi,

(05-12-2023 11:43 AM)Steve Simpkin Wrote:  

(05-12-2023 07:48 AM)jonmoore Wrote:  My favourite 15c related video is the legendary William Kahan talking about the evolution from the HP-34c to the 12c and 15c, [...]
https://www.youtube.com/watch?v=5mBw7tnRx1c

A great video excerpt from Dr Kahan

Indeed. A little earlier in the same interview, he says (my highlights):

"Well, we could go on now with more of the Hewlett-Packard stuff because I had another ambition: the HP-15C. That was my ambition. I wanted to have a calculator that could be used by practically all engineering and most science students.

And I wanted that calculator to be able to do all the math they were going to use up to their sophomore year except for divs, grads, and curls because on a calculator, you can’t really display regions and things like that. But you could certainly do everything else."

However, on the other hand he was very dismissive of the HP-71B, despite it implementing his IEEE math and being at least two orders of magnitude more capable than the HP-15C (and only 4x more expensive). He says about the HP-71B:

"KAHAN: [...] But it only accepts Basic, or a kind of assembly language; it runs slowly; it’s got a very limited window. It’s got sort of fraction-of-a-line window, so you can’t even get a whole line of Basic in there sometimes. So it’s not a pleasant thing to use unless you have relatively simple computations. [...]

[...] also, it was expensive. You could afford it to control laboratory instruments—but if all you wanted was a handheld calculator, that was a lot of money to pay and it was easier to use a PC. [...]

HAIGH: So was that the only machine that was built to the standard, or did other people take it up, too?

KAHAN: That’s the only one I know about whose hardware was designed for the standard, and even that is a little bit stretching because, of course, this is actually a very rudimentary microprocessor microcoded from ROM to perform arithmetic in a certain way."

V.