HP Forums

Maybe already known by some of you, but I just watched this video:
Kahan on HP calculators: Solve, Integrate and Matrix Operations
about his contributions in the 34C then the 15C.

Also this video:
Kahan on creating IEEE Standard Floating Point
has connections with the design of the HP-71B math core based on this standard (NaN, Inf, denormalized numbers, exceptions, ...) and shows well the contributions of prof. Kahan.

J-F

Thanks for sharing those links!

Very nice indeed, thanks! I reposted over here with a few more links - there's a 200 page oral history which looks fascinating.

(11-13-2021 07:57 AM)EdS2 Wrote: [ -> ]... there's a 200 page oral history which looks fascinating.

It is. When I downloaded it I started reading it- and read the whole thing!

The Kahan calculator video inspired me to look at the HP-34 docs
at "literature.hpcalc.org". Programming on the hp-34 is very similar
to programming on the hp15c and dm15l.

Thanks.

(11-13-2021 01:41 PM)John Keith Wrote: [ -> ]

(11-13-2021 07:57 AM)EdS2 Wrote: [ -> ]... there's a 200 page oral history which looks fascinating.

It is. When I downloaded it I started reading it- and read the whole thing!

If you don't want to read it all, the section about Kahan's work as HP consultant starts at page 144.

Kahan talks about the reasons and the conditions of the accuracy improvement of early models (the well-known 2^3 problem, see this discussion), I didn't know he was involved in that.

But Kahan says (p.147) that the first HP with the improved accuracy was the HP-27, maybe wasn't it the first to be released?
Or it may be a mistake, because Kahan then speaks about the "top row of the calculator’s keyboard, they had these five keys: n, i, pv, pmt, and fe." that are more or less the 5 top keys of the HP-22, not the HP-27.

Also it is clear that the Kahan's improvements of the financial equation solver lead the path to the general solver introduced in the 34C.

There are some mentions of the HP-71B and the connection with the IEEE-854 draft standard, on pages 196-197.

J-F