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Comment by throwaway7645 | Hacker News Reader

Same thing with my dad, but at university level as he could write engineering programs to help with homework and avoid booking time on the mainframe.

Btw: Would you please ask your father what type of calculations he ran on his calc as a power systems engineer? Fortran would've been around for state-estimation and contingency analysis by that time if he was in transmission. For distribution I could see him doing fault analysis or calculating line parameters. If he was on the generation side I'm not really sure what he'd be calculating (not my area). Of course utilities were fully vertically integrated during that time frame, so he could have done a mixture.

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I'll ask the next time I talk to him. I know he worked on high voltage transmission.

Awesome...same as me. I'd love to hear how they did things in more resource constrained times.

I also have a hobby interest in HP calcs (own a 15-c), so double interest here. Not sure if you're a blogger, but that is some legitimate history with the early usage of handheld computing to aid science & engineering. A blog post would be great, but I'd settle on a reply here.

I'm a past blogger, but I haven't kept up with it for a while.

Here's what my dad wrote when I asked him:

The work often involved transmission line impedance calculations. These and other power calculations required a great many translations of rectangular to polar coordinates and back again. We had an Oliveti vacuum tube machine in the office that would only do this one operation in one direction or the other. Otherwise it was back to slide rule, pencil and paper. We had an IBM 360 in the basement that would do grid system power modeling. These calculations required 24 hours to get an answer.

Mom got me an HP-35 for Christmas. It was like touching an alien spacecraft technology.

Later on around 1976, I operated a consulting and substation design business. In this activity I needed to do hand calculations of short circuit current for industrial customers again using the HP-35. The HP-35 was an important tool and a real game changer for electrical engineering work.

Thanks for the reply! It was a very interesting read for sure. The polar->rectangular conversions can be done with an $15 Casio FX-115ES from Walmart pretty easily although RPN is much nicer than scrolling around a bunch when the equations get long. He might already know that, or find it interesting. I've never heard of an Oliveti vacuum tube machine, but will look it up. The IBM 360 machine he mentioned is probably not that different to what we do today (I bet the software has only changed in minor placed). The biggest difference is it's moved to Nix or Windows and off the mainframe and we can simulate massive scale problems in seconds. Of course that means we steadily increase the scope of the problem until you get a process that takes 24 hours ;). I'm impressed with anyone who can use a slide-rule for anything more complex than multiplication. Props to your dad btw. I love my job and it's fascinating to see how past engineers managed to essentially do the same things with tools that seem archaic today. I guess this is similar to modern day software engineers on HN getting really excited bout the Xerox Alto Smalltalk machine & the Symbolics Lisp Machines. The past is neat.

> I'd love to hear how they did things in more resource constrained times.

I found this to be very good: http://www.hpmuseum.org/software/soft41.htm

And I've got this book from 1976: https://www.abebooks.com/book-search/isbn/0830668535/

It covers several different calculators too.

Thanks for the gems. It's been awhile since I've been to the HP Museum page. The Circuit Solver example is pretty cool, but that is a lot of keystrokes haha:

http://www.hpmuseum.org/software/41/41elcirc.htm

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