BitcoinTalk

Difficulty: More nodes active, or faster nodes?

193
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BitcoinTalk
#1
From:
Ground Loop
Subject:
Difficulty: More nodes active, or faster nodes?
Date:
The recent upticks in difficulty have been remarkable.  At 511.77, I've even stopped off those machines where I don't pay for marginal power consumption.  My calculation is that the wear/tear from elevated temperatures and full-speed fans has more risk and cost than the BTC value.   (You can question my math.)


But my question is this: Are we seeing the rise of mega-power machines, or just an exponential increase in the number of nodes?  That is, are the top-producing machines making leaps in power (over average), or are my machines still about average, just dwarfed by the number of participating machines?  Is there any way to tell? (node counts?)

I totally understand that difficulty reflects the state-of-the-art in client khash improvements, but it's clear that my own computers also represent a rapidly diminishing part of the total network generation rate.  As the network gets larger, my chance of finding The Block every 10 minutes shrinks.  I'm thrilled, not bitter Smiley , but I'm curious to understand what has transpired over the past three weeks to make it so dramatic.

Cheers.
BitcoinTalk
#2
From:
lfm
Subject:
Re: Difficulty: More nodes active, or faster nodes?
Date:
Quote from: Ground Loop on August 17, 2010, 07:25:38 PM
The recent upticks in difficulty have been remarkable.  At 511.77, I've even stopped off those machines where I don't pay for marginal power consumption.  My calculation is that the wear/tear from elevated temperatures and full-speed fans has more risk and cost than the BTC value.   (You can question my math.)

This is just what one should naturally expect. Some people have more tolerance for the cost of mining than others.

Quote
But my question is this: Are we seeing the rise of mega-power machines, or just an exponential increase in the number of nodes?  That is, are the top-producing machines making leaps in power (over average), or are my machines still about average, just dwarfed by the number of participating machines?  Is there any way to tell? (node counts?)

I'd guess both. There is Art with his GPUs who claims to have about %10 of the generating power.

Then I see about 850 connections to the IRC channel. Not sure what its been like historically.
BitcoinTalk
#3
From:
MoonShadow
Subject:
Re: Difficulty: More nodes active, or faster nodes?
Date:
I would be willing to bet that someone used one of these...

http://en.wikipedia.org/wiki/Field-programmable_gate_array

to do this...

http://www.springerlink.com/content/765kta4qr92daea8/


which is something that I, myself, obviously has considered.  Whoever is doing it is probably representing a great deal of the current hash percentage, and hogging a pretty good amount of the new bitcoins.  Considering that up to four of these programmable arrays are used by modern ham radios for this...

http://www.dsptools.com/Radio.htm

and this...

http://www.softrockradio.org/


The successful coding of the sha-256 algorithim into a fpga and recoding of the bitcoin client's generation function to use one or more such fpga's would produce a khash per second rate that no desktop could match.  It would look like a super-computer from our perspectives.  As a ham radio operator myself, I was aware of these devices, but I don't presently own any.  Even connected to my netbook over USB2, the khas/sec rate would be sick.  The program for these things are normally kept on the master computer's harddisk, and only take a few seconds to swap out; so a ham could use his software radio whenever he wants to, and then rewrite all of his FPGA's with the sha-256 algorithim before going to bed, and make money while he sleeps.

Another possibilty is that someone owned or bought one of these...

http://www.via.com.tw/en/initiatives/padlock/features.jsp


or some other cryptographic coproccesor on a daughtercard.


I'm sure once Bitcoin takes off, anyone with enough of the coins to have a deep personal interest in the strength of the currency will be running clients with hardware exceleration for the sha-256 has function.

That also makes me wonder if there are PCI daughtercards with FPGA's on them yet.  The last time that I looked into them, they were only available as external setups.
BitcoinTalk
#4
From:
superbitcoin
Subject:
Re: Difficulty: More nodes active, or faster nodes?
Date:
block generation on the VIA C7:

http://bitcointalk.org/index.php?topic=758.0
BitcoinTalk
#5
From:
lfm
Subject:
Re: Difficulty: More nodes active, or faster nodes?
Date:
Quote from: creighto on August 17, 2010, 08:51:11 PM
I would be willing to bet that someone used one of these Field-programmable gate array to do this...

http://www.springerlink.com/content/765kta4qr92daea8/

which is something that I, myself, obviously has considered.  Whoever is doing it is probably representing a great deal of the current hash percentage, and hogging a pretty good amount of the new bitcoins.

...

Quote
The successful coding of the sha-256 algorithim into a fpga and recoding of the bitcoin client's generation function to use one or more such fpga's would produce a khash per second rate that no desktop could match.  It would look like a super-computer from our perspectives.

A lot of hand waving there. For some concrete numbers it quotes 53 MB/s and since we only hash 192 bytes at a time, you might think it would do 0.27 mhash/s (but it probably would be less) which is actually within the range of a desktop.

Quote
Another possibility is that someone owned or bought one of these...

http://www.via.com.tw/en/initiatives/padlock/features.jsp

Ya, someone might! They measure out about 1.5 mhash/s. There are many ordinary Intel or AMD CPUs can do much better than that (with a little more electric power input tho).
BitcoinTalk
#6
From:
MoonShadow
Subject:
Re: Difficulty: More nodes active, or faster nodes?
Date:
Quote from: lfm on August 17, 2010, 09:33:14 PM

Quote
The successful coding of the sha-256 algorithim into a fpga and recoding of the bitcoin client's generation function to use one or more such fpga's would produce a khash per second rate that no desktop could match.  It would look like a super-computer from our perspectives.

A lot of hand waving there. For some concrete numbers it quotes 53 MB/s and since we only hash 192 bytes at a time, you might think it would do 27 mhash/s (but it probably would be less) which I beleive is actually within the range of a desktop with a couple GPUs.



Yes, but there are two points that you overlooked.  First, the software transceiver ususally requires four of these chips.  (two for receive and two for transmit, one does digital signal processing and the other does digital filtering of the raw signal.  Said another way, one is the virtual mike/speaker and the other is a virtual tuner.  Not all such software radio setups need four, however)  So if a ham has four of these, all four could be programmed to this end.  The other point is one that I didn't explicitly mention, one FPGA does not equal only one sha-256 processor.  It is possible, even likely, that more than one such processor could be programmed into a single FPGA chip.  These chips are fairly large so that they can 'virtualize' some pretty complex logic circuts, and a talented programmer could program one chip to be several sha-256 processors running in parrallel.  All this, and his main CPU and GPU are still available if still more Kh/s are desired.  Any hacker with the skills to program one or more GPU's in the same system to crunch hashes is already elite, and doing multiple sha-256 cores on a single FPGA would be child's play.  And we already know that there is some elite talent within the Bitcoin community, some who desire to run it, and some who desire to break it.
BitcoinTalk
#7
From:
satoshi
Subject:
Re: Difficulty: More nodes active, or faster nodes?
Date:
The performance numbers posted from a VIA C7's hardware SHA-256 weren't astronomical.  Only in the 1500 khash/s range.  If you think about it, just because it's implemented in hardware doesn't mean it's crazy fast.  It still has to do all the steps.  It's only if simplifying it down to single-purpose hardware makes it small enough to fit many in parallel.  That's not necessarily easy or a given.