Dear all,
My restoration efforts on the Signetics TWIN made a huge step forward with the publication of reverse engineering of its operating system. It took a ridiculous amount of time to re-create over 28,000 lines of assembler code for its 2650 microprocessor, but it was well worth the effort. 
The Signetics TWIN is a microprocessor development system, similar to the Intel Intellec and others. What made the TWIN interesting is its master/slave architecture, with a main processor managing the system and up to four slave processors for prototypes. The master is Signetics’ own 2650 microprocessor, but the slave can be any 8-bit or 16-bit processor. If (when) the prototype crashes, the master CPU is still able to recover and aid in debugging. This architecture makes the TWIN the most complex machine possible with the 2650 microprocessor, or any other processor of the mid-70s.
Tektronix produced a clone of the TWIN as the Tektronix 8002A. Millennium Information Systems was the creator of this machine, and also sold it under the name Universal One.
Based on two TWINs and my private collection of documentation, I believe my website provides the most comprehensive source of information on the Signetics TWIN. But it is far from complete! If you have any other information on this interesting machine, then please do contact me.
Based on the two operating systems re-created I will continue with reverse engineering the other versions of operating systems, including the TEKDOS variant used by Tektronix. There is lots of work still to be done.
In addition to the TWIN I am also working on other 2650-based systems, from hobby computers to video consoles. Although the 2650 never was a popular microprocessor, it does have unique features and charms.
If you have any information that could be of aid, then please let me know.