ATM
Let me try - controllers are used to recording their information on paper strips, the new system is all electronic involving selecting from a drop down menu, cross checking after you have picked from a bunch of similar figures and talking to the pilot at the same time, for the older controllers who did not use a computer until they are 30 plus it is a major strain on their brain power and processing ability thus affecting their ability to pack the traffic in and detect conflicting traffic in the sequencing. Some systems uses a planner to input and update data and a executive controller to talk to pilot. When you try to fly ten FMS, or even five, at the same time you will understand. There are many more problems that CAD dare not admit since the Government has been putting pressure on to place the system into operations ASAP knowing the present ATM system is way past its use by date.