Topic: Are GPU's Satoshi's mistake? - page 4. (Read 8213 times)

The thing is, I just don't see how such a design is possible. Eventually, need for power efficiency will cross the barrier and investments will be made. With GPU's, we had something ordinary computer users could use to get in with little investment. Arguably, it's no longer the case now. With GPU-hostile algorithms, you actually raise the required investment to get a huge advantage, but once the barrier is crossed, no hobbyist will be able to mine for profit. If you can assume that there is an algorithm that is most efficient only on ordinary PC's, then I agree, but it's a very bold assertion.

My take of the matter is, at the point where casual Internet user begins using Bitcoin for payments, mining and even running a node will be out of the question for the ordinary PC, as long as you keep the proof-of-work and blockchain concepts. We could include an additional, alternative CPU friendly proof-of-work protocol in Bitcoin, but I don't think it will help in the long run. At least the current developers were aware of this, deriving from the wiki entries on future obstacles, and I'd assume Satoshi was too. Bitcoin will scale, but the ordinary user will connect to the network with lighter protocols, and obtain bitcoins using conventional methods.

The PC is dying anyway...

(Edit: Also, arguably, mining is something never to be mentioned in the introductions to Bitcoin. IMHO it always had a bad effect on the overall publicity.)

gpu mining helped btc price to go way up.

I don't think he has made a mistake, hindsight is always 20/20

Unlikely. You may have discovered the power of GPUs for the first time with Bitcoin; but when Bitcoin was being designed, the cryptographic community was already very well aware of their computing power for ALU-bound workloads like SHA-256 which mining is based on.

I don't understand why you consider GPUs as being a "problem" presumably because the average user without a GPU farm cannot compete... The average user, by definition, owns an average PC that will run workloads at an average performance. It is inevitable that specialized hardware will appear and significantly outperforms him. Even if mining was done by an algorithm designed to be costly to implement in hardware (like Tenebrix using scrypt), this would cause miners to evolve toward specialized hardware like many-core server farms.

I do not know whether or not he had though about GPU's or FPGA for mining, but he did put in difficulty adjustments, so I'm pretty sure he thought about better hardware coming out in the future.

It is even worse than you think.  All commercial SHA coprocessors are built for streaming, which doesn't work for bitcoin.

Exactly.  What makes it even less likely than other changes is that GPU have the majority of hashing power.  This GPU miners would in essence have to vote against their own interests.

Bad.  Very bad actually.  The throughput is in Mbps.  A hash is based on 512 byte message. A bitcoin solution takes 2 hashes.  Thus Mbps/1024 ~= MH/s.

For their example FPGA it is in the ballpark of ~1Mbps.  The FPGA developers on this forum have achieved far more.

As for ASIC being a stretch.... it all depends on how big bitcoin gets.  If it gets large enough (i.e. 10% of the transaction volume of paypal) then someone will develop ASICs.  Likely though they won't be for sale and will be retained as a competitive advantage.  Imagine someone like Amazon installing a bitcoin hashing card (based on custom built) ASIC into 100K computers in their cloud.  They could still run virtualized instances on demand but the same "host" would also mine 24/7 on highly efficient hardware.

My understanding is that this kind of agreement would require the agreement of the majority of the computing power of the BTC network and so is next to impossible? Am I mistaken that the Bitcoin protocol was built explicitly so that these are difficult to change, not easy?

Agreed, it is not essential - it's an aspect of the Bitcoin protocol. I'm not sure if I'm on the Jury or not, but if I were I'd have to agree with Satoshi and say CPU-friendly mining is a desirable feature to help drive adoption.

I'm interested in the new developments with Fairbrix and Tenebrix - but clearly Bitcoin has all the momentum.

bitcoin specific ASICs seems a bit of a stretch at this point, but I wonder can something like this not be used:
http://www.cast-inc.com/ip-cores/encryption/sha-256/cast_sha256-a.pdf

Anyone have an idea how to interprete the performance numbers and how they compare to our gpu's?

Thanks - very revealing quote there. My reading of it is that he became aware of the GPU problem after the 'horse had already bolted' - and is thus appealing for a 'gentleman's agreement' for what he might have otherwise prevented in design from the outset.

Thanks - yes, I had forgotten this entirely. Factoring this in, I'm guessing that a sufficiently well designed CPU-friendly currency could make commercial mining entirely unviable. 

None taken and I agree. And I say this as someone who mines, has been fascinated for years with the concept of monetizing distributed computing and was initially drawn to Bitcoin in large part due to its enabling of it, and whose primary skilled contribution to Bitcoin is analysis of mining pools reward systems.

But I think that people are vastly underestimating now the magnitude of the problems Bitcoin will face in the future related to the economics of mining. Maybe "mining for the masses" could play a part in the solution.

At the risk of offending miners...

Seems to me that mining is something of a sideshow and and a system engineering problem who's solution does not matter very much as long as it works.  But I would suspect that Satoshi would have been aware of the possibilities for solving the chosen proof-of-work problem and put at least some consideration into it.  The evolution from CPU -> GPU -> ASIC overlayed with the rate of inflation seems to me to be yet another impressive (and probably non-accidental) happenstance.

I have some wonder about what will happen as ASICs come on-line and how that will occur, but don't understand things well enough to decide whether I have concern or not.  It does seem to me that a lot of the problems that could crop up should attackers gain the upper hand at such a juncture could be addressed by the 'sledgehammer' approach of addressing them in code.

Not only did Satoshi planned for an increasing amount of power being thrown at mining, but he did know that GPUs would exel at it, way before any GPU miner even existed, in December 2009:

No, he means that specialized GPU miners in equilibrium will be close to breakeven and so spend ~$5 electricity per BTC (which ignores all other costs, but whatever), while he as a CPU miner will have to spend $50.

You have it backwards. GPUs are far more efficient than CPUs in electricity use.

The jury is still out on whether this is a problem. Having ordinary PCs viable for mining causes a significant botnet risk, and while the idea of everyone being able to mine is appealing, it's not essential.

If this is agreed to be a problem, the hashing function can be changed to something for which ordinary PCs are more suitable, and it's possible this was Satoshi's plan.


I doubt that, GPGPU isn't exactly news. He might have not known a priori exactly how good GPUs are for SHA-256 but the idea would certainly have occurred to him and he could have investigated if he thought it was a relevant problem.

I doubt that, someone who understands probability (which Satoshi does) and expects that many people will mine (which I believe he did), can't think that solo mining will be feasible.


This has nothing to do with it. This isn't computing in general becoming faster, it's about specialized hardware for this specific purpose putting people using commodity machines at a disadvantage. "Computing power increasing with time" benefits pros and amateurs equally.


You're ignoring capital expenditures. At-home miners are leveraging existing hardware giving them a huge advantage over specialized businesses. To specialize mining, the advantage of the specialized hardware should be equally huge. This is the case with SHA-256, but not necessarily with a function chosen to require resources similar to the average PC.

it doesn't matter how you call it, Pentium, Xeon, GPU, FPGA, ASICs, Quantum computing

it's a computing power which over time going to increase. I don't think Satoshi expected people would be mining Bitcoins in 20 years on the same Pentiums it was developed to run on at the time.