(12-28-2020 06:38 PM)hth Wrote: I think contrived is the word, possibly also "perfectly presented to suit the particular key entry model".

I used the HP-41 for years in school and the "real world", solving all kind of problems including math problems and engineering caluclations. Once you learn how to do it, it was just natural and easy. I never had any problems with the 4-level stack. Well, once or twice perhaps, but then I just knew it and used a storage register to assist.

Two things are worth mentioning though. Today I find the 4-level stack somewhat more limiting than I did back then. I think I got spoiled by RPL and computers and now find it a little bit more of a struggle from time to time. Back then (when I did it all the time), not at all.

Second, I remember one time back in school sitting next to a friend who had a TI-58C (he later got a HP-15C). He was not much into HP early on, but gradually shifted over to the thinking model of it. We had a quite elaborate and tricky math problem to key and we both tried it on both machines. We both failed doing it on the TI, but we both got it right on the HP-41. I think the reason was that you were more involved in solving the problem on the HP and could do it gradually, while on the TI model you just had to key and prey that you did everything right. Problems were not always written out the way you keyed them in on the TI either. Often it was shown as a math formula so there was some mapping to a keyed in calculation on both machines. On the TI you had no idea what was going on, while on the HP model you got intermediate results that were easy to understand and confirmed that you were doing it right, step by step.

Yeah, this example is obviously quite contrived, but I'm sure we've all run into at least one formula where naively diving in at the left will overflow the stack. I don't know that an 8-level stack to match the TI would have made any practical sense, but an extra level or two would have been welcome, and I know I've run into plenty of situations where I have to try really hard not to lose something off the top when writing a program. I'm just surprised I've not seen any talk of it newsletters or literature from the era.

On the TI, I think the bigger risk of plugging in a whole formula is not so much that you aren't seeing the intermediate results quite like you are with RPN, but rather you're at the mercy of the crummy keyboard not sabotaging your efforts with a bounce that goes unnoticed.

(In fairness, my 58C actually has a pretty good keyboard, only requiring an occasional second/harder press on the D key.)