Greenbank based on VLBA with significant modifications

VxWorks hardware for real-time control, some limited interaction with SUN workstation during tracking
Non-Real-time functions performed in Unix workstation environment
Most of low level infrastructure code taken from VLBA
High level Scheduling/monitor software completely re-written
Very low data required for VLBA interface, easy remote operation
Fully automatic tracking done under some circumstances
Full data processing test before each tracking pass
Pointing tests using planets and fixed astronomical sources
Astronomical observations done using system spare time
Full-time operator staff, plus scientific operators