An illustrated online book on Hewlett-Packard equipment
blog.adafruit.com
blog.adafruit.com
The computer in the back with the magnetic tape drive and thermal printer is an HP85a. We had one of those in about 1982-ish, which my dad bought for home use since they used HP equipment in his lab at work. My friend who had a Sinclair ZX-81 would marvel at the fact that (since we had an expansion cartridge) it had a mighty 32K of ram! Absolutely vast in comparison to the 1k of a ZX-81. The HP85a came with really great manuals which taught you how to program in basic, and had a wonderful keyboard. I have a ton of mechanical keyboards and I only once managed to get keycaps that feel as nice as the ones on the HP85a.
That calculator (which I think is an HP-67) also has some history for me. I can’t be exactly sure of the model number, but that looks like the one which was the first RPN calculator I ever programmed. My dad gave me some pocket money to translate a FORTRAN program he had written (which estimated something or other to do with some chemical process) to run on that calculator. He was really excited by the fact that a program he had written to run on an enormous university mainframe that took a whole floor now could run on a thing he could carry well, if not in his pocket (it’s a pretty chunky calculator) at least in his briefcase. That calculator has a really cool red segment display. Really an incredibly capable device due to wonderful design, it (like all HP RPN calculators) allows you to program literally any repeatable algorithm you can execute by hand on the calculator because it’s just a stack machine and you have everything you need (eg conditional branches etc). So that first program I wrote on it was using Newton-Raphson for something or other for example.
HP calculators used to be wonderfully robust so even a clumsy 10-ish year old like I must have been at the time was able to mess around with it in complete confidence that I wasn’t going to break my dad’s work device. There is a legend that a zookeeper was using an HP-12c calculator once to calculate ratios of ingredients and dropped it into the feed. The story goes that the calculator passed through the digestive tract of a hippo and was still able to calculate the yield to maturity on a bond (after cleaning). Source for the story (search for “tough construction): https://www.hpmuseum.org/hp12c.htm
The calculator survived the hippo's digestive process as well as the washing that followed.I have learned much more from those manuals (and also from the manuals of many other companies which have disappeared or from which only empty skeletons survive, even in the case when they still have big revenues, e.g. Tektronix, Motorola, National Semiconductor, Fairchild, General Electric, Philips, Siemens, Thomson and many others) than from most university textbooks.