I found it interesting that the bitaddress.org paper-wallet generator could be used offline if you saved it to a file. The images within worked offline, QR code generation worked offline, etc.

Poking around inside the HTML, I saw that images were stored as base64 data loaded with the data: URL scheme, a trick I hadn't run across before:

<img src="data:image/png;base64,......." />

This led to a brain-fart: why not base64-encode the entire page and paste it into the address box in a browser? If your browser has some sort of bookmark-sync mechanism, it'll even get sent to every other machine using he same browser (though FWIW, this hasn't worked for me all the time on Chrome).

With all that said, have a look at this.  Within you'll find two text files. Copy and paste into your browser's address box. One is a copy of bitaddress.org; the other is a QR-code generator I swiped off of Google Code, modified to show at a reasonable size on an iPhone. I used Firefox Sync to transfer them into iCab, so now I know I have a QR-code generator that runs locally on my iPhone without consulting with an untrusted website.  (You can view the source in your browser to verify that it isn't calling any external resources.)

I bit the bullet...or pepper, as the case may be. :-) In the meantime, I might still snag a Radeon 7750 (as suggested above) or 7770 to tide me over...it's not a huge expense, and even after ASICs take over the Bitcoin world (assuming for the moment that they do), it'll still be much faster than my 9500GT at cranking out vanity addresses and similar tasks.

A bit late to the party, but I'm in for two Jalapeños.  #6535, about BTC28.62.  First time I've paid for something with Bitcoins, too.

Yeah, I noticed when I cut the block payout to 25 BTC that nearly half of the GPU's output gets eaten up by utility costs. 


I found that in another thread.  I'd kinda like to get something going sooner than that.


Did you mean "used" and not "user?"  I had looked at eBay pricing for the 7970 and found prices in the high $300s there.  I just ran the numbers for the 5830...it would be cheap enough (might not even need a power-supply upgrade), but it would start out burning about a third of its earnings in electric costs.  Maybe if I use it to replace the 9500GT in my work computer...would probably need a new power supply to do that, though.


I have, but I'm looking for something more near-term.  Maybe whatever I end up buying can have its earnings directed toward adding an ASIC as the next upgrade.

One other thing:  I'd swear I saw the ModMiner backplane selling recently for ~$100.  Looks like it's now at $190, which raises the total price of getting into that.  It'd still be $250 per FPGA to expand it in the future, though, which would help a bit.

Not recently...think it was about a year and a half ago.  The prospect for that happening again does look somewhat bleak.

Right now, I'm managing ~35 MH/s across four systems with a mix of CPU and low-end nVidia GPU (9500GT and 210...tried the Ion too, but got less than 1 MH/s from it) mining. My earlier CPU mining efforts actually generated a block, so I have some coin to invest in more appropriate mining hardware to bootstrap my way toward possibly producing a usable income stream.

At first, it looked like an FPGA miner was definitely the way to go, but after looking into things in a bit more detail, I'm not so sure.  Have a look at this spreadsheet I knocked together:

BTC calc spreadsheet

Electricity cost is what NVEnergy is charging residential customers these days.  (Electric cost for my existing hardware is a guesstimate, and not all-inclusive as one GPU miner is at work and one CPU miner is a Linode VPS.)  Exchange rate and difficulty were last updated earlier today.  This static analysis doesn't even try to account for changes in difficulty or exchange rate over time, but it shouldn't be too bad for drawing comparisons between different devices.

By my calculations, the options that will pay for themselves in the least amount of time are the BitForce Single and the Radeon 7970.  The Radeon is the cheaper of the two and is readily available (pricing is the lowest price available at Newegg; a quick check of eBay indicates I might be able to save a little bit more).  If ASICs end up taking Bitcoin mining by storm and render the Radeon useless for mining, I could always unload it on eBay to a gamer.  (I don't play games. I've stuck with nVidia GPUs up to now because they're dead simple to get running under Linux and VDPAU provides pretty effective HD H.264 and MPEG-2 decoding acceleration.)  OTOH, my home office is already warm enough.  250 W would be a fair amount of extra heat I don't really want or need.

The BitForce Single is more productive and uses two-thirds less power, but from what I've read, it seems like availability is a bit of a mixed bag.  It helps that Butterfly Labs takes Bitcoin directly for payment, but if I hand over a fistful of bitcoins today, how long would it take to receive hardware from them?  With the Radeon option, once I have some coins cashed out to dollars, I can place an order with Newegg and have the goods in a couple or three days.  80 W is another point in its favor.

The ModMiner and FPGAMining options also look interesting, though my finances would only allow a two-FPGA configuration at the start.  They'd earn about a third less than the Radeon or about half as much as the BitForce Single.  That would be that much more time before I can reinvest what they earn into more hardware (though the ModMiner could be expanded more frequently by adding one FPGA board at a time).  20 W isn't much more than a CFL lightbulb and would barely have an effect on my electric bill.  I haven't seen any complaints about availability or shipping delays.

Bottom line: I'm a bit torn as to which way to go.  The Radeon provides decent productivity at a lower cost, but would double as a space heater I don't need.  The expandability of the ModMiner is a point in its favor, as well as its frugal power consumption (which lends itself to acquiring a larger number of them as time goes on). The BitForce Single is the cheapest quad-FPGA option by a long shot, but how long will I be waiting if I put in an order for one?

Which option would you pick?

A couple weeks ago, I dusted off the wallet on my VPS that picked up 50 BTC from mining about a year and a half ago. (It's no longer on my VPS, BTW.) I figured I'd do some small transactions to see if it'd work...started with .0001 BTC to a Blockchain wallet on the 9th, followed by a .01 BTC transaction to the same wallet on the 15th or so.  It took until the 22nd for both to be included in a block.  Fees were included with both (.00004096 BTC for the first, .01 BTC for the second).  By comparison, the .01 BTC transaction from the Blockchain wallet to my cellphone (and the transaction by which I reclaimed the send) took just a few minutes to find its way into a block.  Is this normal? 

Since I'm still stuck here for now, I thought I'd ask.  I've poked around in the hardware section, and it's clear as mud which way I should go.  I'm thinking that an upgraded GPU isn't the way to go, as it sucks down lots of power (and I'd most likely need a bigger power supply to go with it).  That leaves FPGA and ASIC as options, but what's the cheapest way to get going?  I understand that ASICs aren't yet shipping, and that while they promise to be a good bit faster (and maybe cheaper), substantial changes to the way Bitcoin works could render them expensive paperweights.  I'd like to get beyond the ~25 MH/s I'm getting with the CPUs and low-end GPUs I have; what's going to be the best bang for the buck?

Hi. :-)

First ran across this site a couple of weeks ago...some CPU mining on my VPS paid off a while back. I'm only managing about 25 MH/s between a Core 2 Quad Q6600, a couple of GeForce 9500GTs, and whichever Xeons my VPS is running on, but I'm considering stepping up to something more powerful.

If you want to have it run at certain times and not at others, a couple of cron jobs to start and stop your miner will do that. Setting a high nice value should also help keep it from killing your computer too badly while you're using it.

Sometime back I don't know how long ago, I set up bitcoind on a VPS I had at Slicehost. I figured I had CPU time available that I wasn't using, so why not? I got lucky, generated a block, and scored 50 BTC. It took me a while to figure out this had happened...think it was back around March 2011. A couple months later, I migrated my VPS to Linode. 

Skip forward a few months...Linode's web interface allows someone to make off with some wallet files with keys to a fair number of bitcoins.  I didn't think much of it at the time...didn't have bitcoind running.

Skip forward to a couple weeks ago...decided to take another look at all of this Bitcoin stuff.  With a wallet worth somewhere around $500 if it's intact, I figured I'd have money for some toys, at least. After some trial and error, it appears that I'm not one of the eight Linode customers whose wallets were hijacked. Yay me. :-)

I've moved the wallet file off of Linode to a Linux box at home. I've figured out which addresses have my coins. Blockchain.info has the addresses so I can see what I have, but the private keys live on paper wallets (PDFs of which are on a flash stick on my keychain).  I think I've gotten a better grip on how Bitcoin works and how to do things reasonably securely.

I guess that's long-winded for an intro, but it is what it is. :-)