I had a similar sort of experience with both a 48SX and a 48GX. They were great little portable computers back in high school, but as soon as I got better acces

I had a similar sort of experience with both a 48SX and a 48GX. They were great little portable computers back in high school, but as soon as I got better access to bigger machines, I lost interest/motivation. With that said, there are some technical aspects of the 48 series that were particularly gratifying. The unified programming model (RPL all the way down to assembly) and focus on customization made it easy to extend the calculator in interesting ways. (ie: I remember writing a reasonable improvement to the stack display in a couple hundred bytes of user code, etc.) The USAG command was another fun example. The HP48's programming language was dynamically typed... every user command had a standard type check/dispatch prologue at the beginning of its code that would check the arguments on the stack and dispatch to the right block of code based on types. What USAG did was to take the name of a command, inspect the code to look for what combinations of types it could accept, and then present those in the UI a form of 'online help'. (Editing RPL programs worked similarly... the calculator didn't retain the text of a program you entered, it would reconstitute the text by inspecting the 'compiled' code). Reading back over those examples, they aren't the kind of thing you'd expect to write about a calculator... which is part of what made the HP48 series so much fun.