Non-cloud servers. With cloud (virtual servers) you don't have to deal with for examples harddrives, network cards because that is all abstracted away. It's a different set of knowledge required.

like industrial applications maybe some refer to as old school. IoT, mainframe, hardware, kernal, OS's, that kind of on metal I guess web is a chop shop kinda always has been. There is a ginormous world of software that isnt web!!!