I flew with on an Il-76 before in the Nav Compartment..
Was interesting, but luckily it was day VFR, otherwise it would've had been quite scary.
I figured that is some sort of flight computer, but exactly what inputs there are wasn't clear. There was some valves still in the aircraft, so as far as INS goes, might be pushing it. IRS more likely.
The nav was punching every now and then, so I think it's more of an automated dead reckoning computer that interfaces with basic autopilot etc.
Please don't quote me on this, but I really didn't see any 'smart/electronic' inputs into the system.
On-board Direction Consultant