 Computer systems are now coming back online and businesses are scrambling to get back on track after many had to roll back the years and resort to pen and paper. Well, despite the issue being fixed, CrowdStrike's CEO admitted it could be some time before all systems are back up and running. Professor of Computer Science at Oxford University, Nigel Shadbolt, says the outage illustrates the world's reliance on a small number of cyber security companies.