Einstein Platform is NewtonOS running on other operating systems.

It currently runs on:

MacOS X (ppc and x86)
Linux (with X11)
Windows

ARM-Linux PDAs:
Zaurus (with OpenZaurus)
Nokia Internet Tablets 770 and N800
PepperPad 3

Note: Einstein requires a ROM image from a MP2x00 US, MP2100 D or eMate 300.