Photos: The computers that kept our skies safe for the past 40 years

Eye on the sky

In the past three decades the number of aircraft entering British airspace has more than doubled.

With more than two million planes flying over the UK every year, exponential gains in computing power have been essential for helping air-traffic controllers cope with the growing number of flights

"The biggest change has been the number of aircraft we can move through airspace. We've doubled the capacity of the UK airspace and done it safely with more fuel efficiency," Gary Gibson, general manager of engineering design at the National Air Traffic Control Services (NATS), said.

Safely squeezing more aircraft into the airspace has, in part, been made possible using computer modelling. By using network flow dynamics to calculate the optimal arrangement of aircraft for safety and efficiency, NATs has been able to increase airspace capacity by 30 percent, Gibson said.

It's a long way from where the National Air Traffic Control Services (NATS) started out in the 1960s.

This rather unusual looking machine, the Independent Radar Investigation System (IRIS), dates back to those early days.

During its 34-year lifetime, IRIS helped controllers at NATS London Area and Terminal Control Centre watch over 48 million aircraft journeys.

The fishbowl display marked all aircraft within radar range using vector graphics. Driving IRIS' radar display were four Digital Equipment Corporation PDP-11 minicomputers.

The IRIS is part of a new display charting the history of the technology used by NATS at The National Museum of Computing in Bletchley, Buckinghamshire.

Image: Nick Heath / TechRepublic

By Nick Heath

Nick Heath is a computer science student and was formerly a journalist at TechRepublic and ZDNet.