Possible Clues:

• Of computer system, able to respond immediately to input
• Ignore altimeter, holding with immediate feedback
• When something actually happens
• In Spitfire, altimeter compatible with type of air-traffic control system?
• Of computer system, responding instantly to input data
• Fast-acting mode of computing
• Right now, or before Portugal adopted the escudo?
• What some online games are played in
• Hours actually elapsed
• Live, as footage