Web-infrastructure firm Cloudflare was hit by a global outage on Tuesday, leaving major internet platforms inaccessible globally.This is the second major internet disruption this year, following the malfunction of Amazon's cloud services unit, AWS, in October.Here are some of the biggest tech outages in recent years, in chronological order:British AirwaysIAG-owned British Airways was hit by a major computer system failure in May 2017 that stranded 75,000 passengers over a holiday weekend,