emuStudio is a toy-computer emulation platform and framework, targeting mainly academic sphere. A platform, because it supports full emulation “life-cycle”. From writing and compiling programs for emulated machine, to running and debugging. A framework, because it provides API and documentation which encourages implementing your custom toy-computer, either real or abstract.
There are already many emulators out there doing great job in preserving history (e.g. MAME, or simh). While emuStudio is also trying to be accurate in technical details and historical behavior of emulated computers, but the main focus is allowing comfortable programming and experimenting with emulated devices - in the style of “write program - load it into computer - emulate”.
That is why you can expect quite detailed documentation of rather usage and programming of the devices than used emulation techniques. That brings along nice GUI, source code editor and virtual computer designer.
The following lists a few references on emuStudio online.