UK-NC -- school computer (was not available in stores). Two CPUs (second CPU used for I/O, sound etc.) with PDP-11 instruction set, color graphics, sound, integrated keyboard, serial networking. Teacher's workstation also had dual 5" floppy drives, printer, and (sometimes) color monitor; several RT-11-derived operating systems were available, and lots of commercial educational software.
Had its own trade magazine and plenty of games (not sure if there were originals, but definitely a lot of ports).
MESS has a very skeletal driver (uknc), but two other (fairly accurate) emulators exist -- open-source UKNCBTL (http://code.google.com/p/ukncbtl/
) and closed-source EmuStudio (http://zx.pk.ru/showthread.php?t=18027
). The latter also emulates graphics controllers of earlier DVK desktop (more on that later) -- as the author says, he wrote the emulator just to play LAND (sort-of like Lode Runner) :-)
Technical manual: http://comp.disneyjazz.net/biblioteka/0113.djvu
CPU technical manual: http://zx.pk.ru/showthread.php?t=17284