return (PAGESZ - sizeof(struct page_info)) / sizes[classno];
Continue reading...
。搜狗输入法对此有专业解读
Still, for all the clever innovations that have made cabins safer, the economics of flight have also potentially made them more dangerous. Planes once furnished with plush recliners and wide-open aisles are now packed with more passengers each year. Those in first class lounge in lie-flat seats with built-in air bags in their seat belts, while those in economy sit shoulder to shoulder and knee to seat back, hoping they won’t crack heads in a storm. In 2021, the F.A.A. published a study on emergency evacuations which concluded that current cabin-seating requirements “can accommodate and not impede egress for 99% of the American population.” But last year a review panel from the National Academies of Sciences, Engineering, and Medicine found that the study was flawed. The F.A.A. trials had included only volunteer passengers with no physical limitations, and none of them was over sixty years old.
This sort of thing is why I think historians need to be more active in technical discussions and decision-making about emerging technology. Everything about our current world is different from the premodern world that our ancestors inhabited. The past truly is a foreign country. But we carry fragments of that foreign world with us in our physical selves, in the gestures and other implicit knowledge we teach our kids. We take it for granted that there are aspects of being human which are never written down and which are unknowable unless you experience them.
Try unlimited accessOnly HK$10 for 4 weeks