The problem with all these arguments is that DOS extenders of the day used to do the same, or more. Do you call DOS extenders "operating systems not shells" too

The problem with all these arguments is that DOS extenders of the day used to do the same, or more. Do you call DOS extenders "operating systems not shells" too ? On one hand you have that the technical answer to the above question is likely "yes". DOS is so simple that any non-trivial application likely qualifies as an operating system. Implementing some kind of virtual memory support is almost a given, and process control is not unheard of. But on the other hand most people would refer to anything pre-95 as "shell" for the simple reason that it requires DOS to boot ; even when complexity-wise, 95 and later versions of 3.x are practically the same: if you call one an OS, you ought to call the other one a full OS too. So this question is on the "angels on the head of a pin"-level; but this simply means there's no answer that doesn't require a lot of nuance, and this also applies to the "it can't be a shell, it does too many things" answer.