When they worked, and only for very small scale calculations.
I bring up this specific era because there was as much skepticism about electronic computers then as I think there is now about quantum computing. They were big and slow even at the small applicable scale, and incredibly unreliable. We had radio; it was comparatively gangbusters. We had telegraph, which also failed a lot but at least was obviously useful. For all the hubbub about computers computing, we knew humans were extraordinarily more capable and had tools like the slide rule to handle calculations at varying scale. I think you'd have a hard time being in computer sales then, even if you knew what today looked like.
Not that I am all that confident about quantum panning out, I'm still in a superposition about it, let's say. But it was what I felt to be an appropriate comment to the root-comment's sentiment "quantum computers don't exist."
Good point about being able to check the answers against reality. It is a big sticking point about anything QED related.
EDIT: oh, nevermind, it appears that comment has since been removed.
In general it's probably wise to be skeptical of new technology. However, I would imagine back then people would have been skeptical because computers were annoying to deal with and of questionable utility all things considered, not because they weren't sure if the computers were even doing anything at all. Imagine having a 20 ton machine that takes up half a room and gobbles up power and people's time, and all it's able to do is print out numbers that relate to nothing other than its internal state.
I bring up this specific era because there was as much skepticism about electronic computers then as I think there is now about quantum computing. They were big and slow even at the small applicable scale, and incredibly unreliable. We had radio; it was comparatively gangbusters. We had telegraph, which also failed a lot but at least was obviously useful. For all the hubbub about computers computing, we knew humans were extraordinarily more capable and had tools like the slide rule to handle calculations at varying scale. I think you'd have a hard time being in computer sales then, even if you knew what today looked like.
Not that I am all that confident about quantum panning out, I'm still in a superposition about it, let's say. But it was what I felt to be an appropriate comment to the root-comment's sentiment "quantum computers don't exist."
Good point about being able to check the answers against reality. It is a big sticking point about anything QED related.
EDIT: oh, nevermind, it appears that comment has since been removed.