[DubiousPusher]

It's honestly just a really bad analogy. Evacuated tubes were not pursued en-masse as an end unto themselves the way quantum computing is being pursued. Their development was as a side fascination for a handful of researchers or they were advanced because they were directly applicable to some goal of a researcher with maybe some mild tweaking. They were not a moonshot and they developed along similar lines as most useful "inventions" of today.

Quantum computing isn't even really comparable to ENIAC. Because the fundamental parts of ENIAC were known to be capable of doing what was required before the machine was built. There were analogus precursors to basically all the parts of the machine. The engineering challenges came with integration and at scale but fundamentally there wasn't a question of whether it could be done or not. We can't say the same yet of quantum computing.

IMO, quantum computing is more like space travel ca. the 1950s. We've got a lot of information: rockets look promising, we've learned a lot about the environment pilots will need to operate in up there, etc but no one really knows how far this can go and certainly we can't say if it will ever be profitable.

[YetAnotherNick]

> It's honestly just a really bad analogy. Evacuated tubes were not pursued en-masse as an end unto themselves the way quantum computing is being pursued

No, it's not. The Vacuum tube was sold for commercial and industrial use starting from 1915 for rectification. And most of the research spending went into it after it shown some promise from commercial application.

Not arguing though if pursuing something just for research is bad, just saying vacuum tube research was nothing like quantum computer research.

[DubiousPusher]

> just saying vacuum tube research was nothing like quantum computer research.

That's what I'm saying. Vacuum tubes had various evacuated tubes as their precursors which had uses in experimentation and industrial applications. This led to a step by step development process with continuous subsequent innovations building on each other. Quantum computing on the other hand is kind of an all or nothing proposition with many problems that must be solved which only produce value when functioning as part of the whole.

I don't think the development of classical computing is a good analogy either as the shared memory computer had various electromechanical precursors that had utility all of their own.

[dr_dshiv]

To clarify the analogy:

Quantum computing with todays technology :: Classical computing in the early era of vacuum tubes

The point of the analogy is to communicate that we are at an early stage of development. Also, I just like vacuum tubes.

[oldgradstudent]

> Quantum computing with todays technology :: Classical computing in the early era of vacuum tubes

There's still a big difference.

Even in the earliest era of computing with vacuum tubes (and even before), they were building machines that produced useful results: artillery tables, H-bomb simulations, cryptanalysis, etc.

Most things these machines were used for were simply impractical without them.

There's nothing even remotely analogous with quantum computing.

[dr_dshiv]

Well, to be fair: quantum computers can do practical computations—but because “normal” computers are so unbelievably well developed, it is not practical to do them with quantum computers.

The earliest era of computing was mechanical. The mechanism of thermionic transmission (vacuum tubes) was invented by Edison in 1883. The Colossus computer, with thousands of vacuum tubes, was the first practical use of vacuum tubes for computation, in 1943. We cannot yet assemble thousands of qubits together. Once we can do that, we will be able to perform many useful functions. However, even with thousands of qubits, many of the functions will be more practical to run on a classical computer (because classical computers are amazing and continue to develop).

[DubiousPusher]

> The Colossus computer, with thousands of vacuum tubes, was the first practical use for computation, in 1943.

I don't think this is true. Perhaps the Colossus is what we would call the "first computer" by some definition but electro mechanical computing devices built for specific purposes preceded it. There wasn't a 60 year gap of investment with no practical application of classical computing.

Classical computing was built up over time with practical utilith along the wya. The vacuum tube eventually became a useful component of it.

[fsh]

No, current quantum computers cannot do any practical computations. The gate errors are astronomical compared to even the earliest digital computers. Any algorithm with more than a few gates will produce just noise.