zlacker

>>lewisf+(OP)
As far as I can tell the TI graphing calculators are riding entirely off of mind share/familiarity, both among students and teachers, and teaching materials, which reinforces the former. Specifically textbooks and teacher training all use TI graphing calculators. Presumably tests are therefore made with the capabilities of a TI graphing calculator in mind.

CollegeBoard actually has a wide range of calculators it allows for the SAT (https://collegereadiness.collegeboard.org/sat/taking-the-tes...), but very few test takers take advantage of this.

TI graphing calculators are based on sufficiently old hardware that it is probably faster to emulate a TI calculator on something with the power of a Raspberry Pi. Indeed an open source third party emulator already exists (https://github.com/CE-Programming/CEmu). Does anyone know what the legality of selling a calculator that is a dedicated emulator of a TI graphing calculator (not just an online one like Desmos, but a purpose-made physical calculator that does nothing else)? I'm curious why this hasn't already been done before.

EDIT: I mean a dedicated emulator that can do nothing else but be a graphing calculator, e.g. not something on a smartphone.

>>dwohni+Ic
HP used to make their own custom CPUs for their calculators, with an architecture designed for BCD arithmetic using 56-bit and later 64-bit registers. In 2003 they switched their graphing calculators to ARM9 processors running an emulator of their old CPU architecture so that they didn't need to re-write the whole OS.

SwissMicros did something similar for HP's non-graphing calculators, recreating the keyboard layouts but using modern ARM processors that run emulators of the original HP calculators. Apparently HP's early calculators did not include copyright notices for their OS: https://nonpareil.brouhaha.com/microcode_copyright_status/