I think this is a bad idea.

If you are really bored, write up a proposal to use the machines. Of course, then your employer would get all the mining proceeds. It is their hardware anyway.

You said it, not me.

It is impossible to fully secure modern computers because they are too complex to fully understand (top-to-bottom) yet are not formally proven correct at each abstraction layer. In fact, since at least 1996, the trend has been to hide implementation details from the end-user. I personally think that the computer industry won't be mature enough to sustain a stable crypto-currency for another 150 years.

There are two competing security concerns when talking about the wallet.dat:

• Security from attackers who want to spend your wallet
• Security from data destruction

Encrypting the wallet.dat by default will help protect against the first security concern, while making the second one worse.

I plan on using full drive encryption, as well as an encrypted back-up. The passphrase would be written down in two locations. The back-up would be stored in a safety-deposit box and never move with the decryption key, though I may store it with the decryption key (in the safety deposit box).

BTW: for secure encryption, the term is passphrase, not password. Passwords are simply not long enough. A passwords made up of random ASCII numbers, letters, and symbols has about 6 bits of entropy per character. I have seen it reported that a 12 character password is "enough." That works out to about 72 bits of entropy. 64 bits of entropy can likely be cracked by a fast computer within a year. 72 bits increases the difficulty by a factor of 256. 128bits is believed to be computationally infeasible to even count during the lifetime of the universe (energy constraints). If your password was ever published at any time during human history, the entropy is probably less than 64 bits (I don't think more than 1.84x10^19 words/phrases have ever been published, even on the Internet).

Since when does the "average" computer have a decent CPU/GPU? To be honest, I have not tested the mining speed of my computers yet.

Edit: My AMD Sempron(tm)   2600+ gets about 685kHash/s with the default client.
Edit2: That works out to a GPU being 438x faster than my "average" CPU. (300MH/s is 30,000 times larger than 10 kH/s)

GPUs are not the only way to mine. Simply the most profitable at this point in time.

My strategy (given away in other posts) is to buy Bitcoin at the 30 day weighted average price. If I am a multi-thousandaire after a year, I will invest in "Big Iron": CPU mining that can scale to thousands of simultaneous threads.

My strategy would be to only mine in response to a drop in overall network performance. The goal would be to buffer crashes in mining capacity, even at a slight loss, in order to preserve the stored value of my bitcoin investment.

People give each other pointers because mining secures the network. There will be other cards.

No. The concern is that the operator can be coerced into doing bad things to the network. Having one person control two mining pools does not solve the problem.

IMO, most people should be solo mining. Most people don't like the prospect of waiting over a month to process a transaction block.

Having thought about it, it is not good, but probably not as bad as it sounds. Batteries don't like very quick discharges or charges. You will probably degrade the batteries faster.

Otherwise, you would have them fail and recover in series. It would be a pain to get any power monitoring software to work correctly.

Unless you are renting a dedicated server, most webhosts will prohibit processes using large amounts of CPU time. Keep in mind that your webhost would have access to the wallet.dat stored on the server as well.

I think this is a bad idea. If you are tripping the breaker, your are overheating the wiring. You really should wait at least 5 minutes before rearming the breaker.

IlbiStarz needs to put each machine on a separate circuit as far as I can tell. He/she already started the circuit mapping by tripping the breaker. IlbiStarz, you did write down what plugs and lights were on the breaker that tripped, right? For lights you can estimate the power draw by adding up the ratings on the bulbs.

PS: For running off of battery power for any length of time, you probably want your rig to draw less than 60W. I think it may be feasible for me to do some mining using solar power at 12watts. 12 Watts is 288 Watt-hours (1.04 MJ) per day. A 12V battery would need a capacity of at least 24 Amp-hours to supply that much load all day (6 amp-hours for a 48V battery). You will want to be able to fully charge the battery in full sun during the day. To do this, the solar panels must charge the battery within ~8 hours (preferably 6). That will take at least 36Watts (assuming 100% battery efficiency) + the 12Watts you are constantly drawing (48 Watts). Round up to a 60Watt panel. For a 60Watt load, you need to multiply all those numbers by 5 (30 amp-hour 48 Volt battery, 300 Watts of panels).

Why am I bringing this up? A UPS loosing power in the form of waste heat will make the breaker problem worse. Sure, you may be able to run for 5 minutes while the wire cools. But then, you will trip the breaker immediately because your 1600 Watt load will become 2000 Watts as you charge the UPS battery. Note: batteries take at least an hour to charge; if you don't want to degrade them over time.

PPS: power usage for computers is difficult to estimate without actually using a watt-meter. Most power supply calculators online over-estimate the power requirements to sell you a bigger power supply. Cheap power supplies can't even supply their rated power. In other words: if both rigs have approximately the same hardware, they should have approximately the same power draw, despite the power supply ratings.

PPPS: for ball-park, 30W for board + rated CPU wattage + Rated GPU wattages + 6W/ hard-disk).

Without rereading the whole thread, I think you are the only one to bring up the velocity of money. To be honest, I never thought of transaction fees as a "tax" on the velocity of money. I personally think that in the long term, mining capacity will follow the stored value of all bitcoins, not the price of power as many expect. If the bitcoin economy becomes a multi-trillion USD economy, all world governments will be mining in a big way. Early adopters and large corporations will be using their capital to set up solar mega-projects and data-centers: decoupling the price of electricity from mining capacity.

In my first or second post, I explain why I think bitcoin will fail in the medium term. The slow dwindling of mining capacity brought on by deflation did not make the list. You may be right. However, keep in mind that bitcoin is still an experiment in its early stages. The first drop in block reward has not happened yet, and will happen within two years (haven't calculated the expected date).

If you are correct, I would expect to see a substantial drop in mining capacity (over 30%), that does not rebound for several months. If everybody else in the thread is correct, I would expect to see a slight drop in mining capacity (for consistency I will say less than 30%) that will rebound within 6 weeks (apparent lead-time for mining to match price according to some on the forum).

If deflation is really shown to be a problem, I think many people would support starting a new block chain where the block reward does not diminish over time (possibly called bitcoin 2.0). Would that be inflationary enough for you, or do you think the block reward should increase over time as a (small) percentage of existing bitcoins?

If I am right about mining capacity following the stored value of all bitcoins, inflation (not deflation) may actually cause mining capacity to drop. Currently, bitcoin is experiencing hyper-deflation, and mining capacity is scaling well.

You can run the chips hotter when using water cooling.

IBM’s Hot-Water Supercomputer Goes Live

The way homes are wired, each "circuit" goes to several different plugs. The assumption is that you won't put too much load on any of them. Where high-drain appliances are expected (like the kitchen), the top plug may be on a separate circuit from the bottom plug. At least in my house, those are still shared among 2 receptacles (found by breaker trip when both microwave and electric frying pan were on at the same time: fixed by using the second circuit).

I calculated in another thread that you can only draw about 960 Watts continuously from a 120V, 15amp circuit if your power supply has a poor power factor (of 0.67 (4 of 12 amps are wasted)). The kill-a-Watt (and similar meters I assume) will tell you the power factor of the load. What is actually important is current draw. If you have an old or cheap power supply, it will have an approximately capacitive load. That causes the current draw to lead to voltage. At the zero-crossing of the wave-form; you are heating the wires with current, but supplying no power (power=current x voltage).

The good news is that the power company does not charge small users for their power factor: only wattage consumed. The bad news is that if you have very bad power factor (anything below 0.9 is bad), you can't use as much power without overloading the circuit. Power supplies with Active Power Factor Correction should give you good power factor. I have also found vacuum cleaners employ power factor correction as well: probably in the form of a capacitor (capacitive load) in parallel with the motor (inductive load).

I think just about the only way to know which plugs and light fixtures are on what circuit is to systematically turn off the  (smaller) breakers one at a time to see where the power goes out. To be honest, I have not yet done that in my own home. It will likely inconvenience all of the other power users

There is no way the value of Bitcoins can keep doubling every 2 days. Since I am thinking medium term, I am seriously considering only bidding at the 30 day weighted average price (currently at $7.98 USD).

In in other words, I think we are seeing a bubble that may correct over 70% over a 2 day peroid.
ie: $18.89*0.3=$5.68.

I don't think that it is necessary for everybody to contribute their computing power. As somebody pointed out, one GPU dedicated to mining can replace 1000 average computers. For the average person (if bitcoin becomes popular) leaving the computer mining would be akin to buying a lottery ticket.

In this thread I was convinced that the average user should mine, but only at 1-5% CPU/GPU time. With millions of users, this incremental CPU power would add up, making the network more secure.

I don't have any bitcoins yet, but if I am a thousandaire  in a year, I will be investing in "big iron." IIRC, the some of the newer Spark-based servers can process up to 1024 threads at once and are very good at integer calculations (used in mining). I suspect one of those servers can hold its own against a GPU miner, albeit at a slightly higher current draw.

My strategy would be to only mine to protect the integrity of the network. To do that I would only turn on threads in proportion to the network hash rate. For example, if the historical network peak hash rate was 4 TeraHashes/second, I would only run: 256 threads when the network is at 3TH/s, 512 at 2TH/s, 768 at 1TH/s, finally only using every available thread if the hash rate drops to something like 3 Gigahashes per second.

Of course, I would use such a box for other things as well, such as acting as a gateway for an open access mesh network. Such a machine should be able to handle multiple VPN connections very well.

You are learning that the cheapest kilowatt (as in kilojoules per second) is the one you don't use.

With careful mapping of your wiring, you may not need 200 Amp service. Your service is 100Amp, 240V. Each "branch" can supply 80 amps continuously. If you know for a fact that different outlets are on different sides of the branch circuits, you probably don't even need 240V plugs. You can check this by using a multimeter to check the voltage between the "hot" contacts in the sockets. If they are on the same side of the circuit, the voltage difference will be less than a volt. If they are on different sides of the circuit, the voltage difference will be 240V.

One thing you will have to watch for is power factor. Most my computers without active power factor correction have a power factor of about 0.67. That means that for every amp of current supplying power, I have half an amp of "wasted" current just heating the wiring. What that means for you is that you should derate each circuit by the power factor of the load. For example, on a 15 Amp circuit, you are allowed to draw 12 amps (multiply 15 by 0.8) continuously. If your load has a power factor of 0.67, you would multiply that 12 amp rating by 0.67: giving 8 amps delivering actual power (960Watts). I recently bought a 380 Watt power supply with active power factor correction: it cost me just over $45 (a little over your budgeted $20 per machine).

You can free up about 40 amps (well, 32 Amps after derating for continuous load) by replacing your electric stove with a gas stove. You can then get an electrician to pull the 240 volt connection over for the AC or even running some of the machines.

Of course, renting actual commercial space is a option. However you should really consider whether you consider this a hobby or a business. If it is a hobby, you don't need every last machine running. You may even want to have a few on standby and only run them if the difficulty level network hash rate drops for whatever reason (or in the event of hardware failure). If you consider it a business, you may need to consider getting a business license. Miners should also be aware that there are only about 50,000 "winners" (blocks) every year.

The modem is so you can keep mining after your ISP drops you like a hot potato for "illegal" activity. The prudent would be working on setting up open mesh networking, but that takes time.

Note: the cheap dial-up plans are often limited to 20 hours/month.

I posted some of my objections in this thread. I have read the last 2 pages of posts and still think it is evil.

I was not aware that it used HTML 5 and workers. On my machine bitp.it idles because my browser does not support the Draft HTML5 standards. That said, my points about non-CPU computing resources  (like memory and available battery power) still stand. Edit: my objection about CPU usage may still stand: what happens if you use 10% of the CPU with a load average of over 1.00? Answer load average increases by 0.1.

There is another problem I did not consider: This script is using a popular mining pool. Over-reliance on a few mining pools weaken the bitcoin network. Web-developers throwing this up on their page are even less likely to implement "solo mining" or even a private mining pool should the need arise. For example, in the event of a pool take-over or shut-down.

Edit: Viewing sites embedding the EMCA script miner at work may constitute a firing offense, just as an IT person should be fired for using company computers to install Bitcoin miners (for personal gain).

bitbid.net has removed the bitp.it miner.

As far as I can tell, the bitcoin protocol does not work if the round trip time is longer than the TCP time-out (2 minutes).

In any case, you can't expected to generate (many) new blocks if your round trip time is longer than the block chain interval of about 10 minutes.

I think this limitation may be serious enough to undermine Bitcoin in the long-term. Somebody on these forums has suggested that isolated groups (like a Mars colony) may simply start their own block-chain for local use. Not sure how exchanges between networks would work. You would probably need to use a trusted courier to move a wallet.dat (for each network) within "range" of the main network periodically.

I hate client-side scripting in general: both Flash and EMCAscript. It takes control of the computer away from the user. There may be some benefit in doing client-side sanity checks or tabulation, but the server must ulimately do those checks anyway since the client is untrusted.

For distributed computing, scripting with an interpreted language is just about the most inefficient way to go about it. Browsers are not Operating systems. There is no way to make a script run at low priority when the CPU is idle. Even if you could do that, you don't know if your use of the client computer is CPU bound. If they are low on memory, your computing client may cause the browser to constantly page out to disk or even crash if swap files are disabled.

I actually don't mind the JavaApplet concept: they actually ask the use permission to do stuff like use the network or disk. The "powers that be" have decided it is a bad idea to confuse users with choice about how they use their computer.