Or you can just set up your backup pool as another miner that runs at a lower priority than your primary (the OpenCL miner in guiminer has a -f option that allows you to set a priority, 30 is the default, bigger number is lower priority).  If/when the primary miner/pool goes down, the secondary miner/pool steps up because the GPU is underutilised.

I use it to switch between btcguild as my primary and slush as my backup and it works just fine.

Up to $17.  I'm just annoyed that I had no cash in my mtgox account to buy at 10. 

You're not seeing the big picture (or at least a different picture to the one I see).

Imagine a world where btc is the default currency used in online transactions.  Mining difficulty is such that the idea of an individual building a dedicated miner is borderline lunacy - the btc made by mining is pretty much exactly equal to the electricity cost of doing so.

So who mines, given that mining is necessary for the integrity of the system?  The answer - everybody.  Your btc wallet is a keychain usb stick with a small btc client that mines whenever powered and internet connected.  Maybe only gets a few hundred MHash/sec (we're talking dedicated custom built hardware), but there are hundreds of millions of these things around the world.  We're talking Peta-hashes now.

And who pays for the portable btc wallet/miner hardware/development?  The pool owners, that's who.  Amazon gives you a free btc wallet with every purchase.  Google give you one free if you sign up for adwords.  Buy a new Toyota and it comes with a btc wallet (and a USB plug to stick it in your car, so you can pay for fuel with btc at the pump).  And the pool owners in general keep the proceeds of mining (we're probably talking transaction fee only by this stage).  Or maybe they give you a discount on your next purchase, or something like a frequent flyer system.

Anyway, that's one vision of a possible future with btc.  But one that I think is plausible if btc "takes off" and lives up to its potential.

Thanks for clearing that up!   There go all my conspiracy theories! 

http://forum.bitcoin.org/index.php?topic=14910

Moderators, anyone?  I asked the OP and he says he didn't lock it.

Thanks

Whats wrong didnt you get in when the price was low enough
There seems to be lots of posters out to scare the price down at the min I cant think why
[/quote]

Seems funny to me too.  The number of people posting "the sky is falling" is crazy.  Now if you stop and think about it for a second, if you were a btc holder and did think that the sky was falling and the bubble was popping, what you would do?  I put it to you that you'd sell all your btc, post a "solong suckers" if you were inclined but more likely just disappear off the map.

Does anyone really think that the doomsayers are really being altruistic and are trying to "save us" from the coming catastrophe?  Or are they more likely to be trolls, or even people trying to talk down the price so they can buy at $7 rather than at $27?

All I know is that I believe in the idea of bitcoin enough that I'm going to keep buying and mining all the way down.  A drop back to $7 (the price where I originally started buying) means I can buy more than I could at $27.  

Long live the revolution!

Screw PCIe ASIC miners, what we really need (and will eventually get, if bitcoin doesn't tank) is a USB miner.  Put your wallet on the USB miner, plug it in to a computer and it starts hashing automatically. 

If I had the time, money or expertise I'd be working on something like this.  Unfortunately I have none of the above - I'm merely an ideas man.   

That's the ticket right there.  The porn industry has lead many times in terms of technology uptake.  Lobby your favourite paid porn site (people pay for porn?) to accept btc, and next thing you know you'll be able to pay your rent with btc. 

What we REALLY need is people to start using bitcoin AS A CURRENCY.  People need to start using it to buy stuff, sell stuff.  If bitcoin gains traction as a true medium of exchange, its value when compared to other currencies will stabilise (relatively).  You are correct that BTC cannot exist as medium mainly for miners and speculators to buy and sell off each other.

Of course you can!  If bitcoins were worth $35USD then I'd happily sell you an oz of silver for one btc.  Given that btc is _supposed_ to be a currency, one measure of its worth is what you can buy with it.

And if you can buy an oz of silver for 1btc, then that makes 1btc worth 1 oz of silver.

You can't measure USD in troy ounces either yet people price silver in USD.

This.

Everyone who wants bitcoin to succeed needs to either give them away to spread the news, or spend them to encourage adoption, IMHO.  Selling is OK too as at least they are being redistributed.

This goes about a million times more for the early adopters who are sitting on piles of btc.

I think Findeton is right - it's absurd - but he's also wrong, as it's interesting.  Right now for me 1btc = a nice meal.  It's a valid comparison.  It's a real world comparison.

When you compare the value of the USD to the GBP you don't say "it doesn't matter what the price is, you need to compare the market cap" because, for one, nobody knows the market cap (all we have are various guesses). 

But at the end of the day, if you have a btc, you want to know what you can get for it.  Doesn't matter if there are 1 million of them or 21 million of them or a gazillion of them - it's (supposed to be) a currency so all that matters is what you can get for it.

And you can almost get for it an ounce of silver. 

I believe the maximum jump is 400%.

blockexplorer.com has an estimate of the next jump, currently 734166.  As for where it could go between now and the next jump - sky is the limit.

According to blockexplorer.com, you need to run on average 2,436,441,257,208,094 to win a block (50 btc).

You want to make $25 per day.  Say that's 1btc per day, given current mtgox price, with the extra $5 for overheads.

That's 50 days to solve a block.

So <bignum>/50/24/3600 = 564MHash/sec

So, if you build a rig capable of 564MHash/sec then you will average 1btc per day or $25 at today's prices and difficulty (although I'd suggest joining a pool to average out your btc rather than wait for the "big payout", given that these numbers are averages).

But... difficulty adjusts every 2016 blocks such that the eta of each block is ten minutes.  At the moment the network has more power than it "needs", so difficulty will adjust upwards in a week to a week and a half.

And... nobody knows what will happen with the value of btc.  If it keeps pace with difficulty then it's a wash.

As for what to buy, https://en.bitcoin.it/wiki/Mining_hardware_comparison

You can't mine profitably nowadays using your CPU, you must use a GPU.  Using a CPU it costs you more in electricity than the bitcoins are worth.  So unless your electricity is free, you need a GPU.

I very much doubt your 3 year old laptop has a GPU capable of mining.  ATI GPUs are best, Radeon HD 5XXX models and later (must support OpenCL).  You can mine with Nvidia GPUs, but they are _significantly_ worse at it than ATI.

As for "having a play", download the bitcoin client, run it (it'll take some time to download the current blockchain - the current record of all transactions), and once it's up to date you can have a play.

See if you can find someone to give you a few bitcents (there used to be a site called the bitcoin faucet that would give away bitcoins, last I checked they'd run out), watch the bitcoins "magically" appear in your account.

Great idea.  Would be nice not to be screwed on international transfers and conversions on mtgox.

It's my understanding that 400% is the maximum increase.

And as for how long it would take to go back down - it wouldn't, unless people stopped mining.  If difficulty and hashing power were in balance then the difficulty wouldn't change.  And if the next jump in difficulty were 400% then that would suggest that there was even more extra hashing power in the network (because the chances that the amount of hashing power in the network warranted exactly the maximum increase in difficulty is pretty small).

EDIT: current estimate of next difficulty is 771795, "only" a 36% increase

I have to say, if I had a supercomputing cluster ready to mine bitcoins, I wouldn't bring it online in the day or two before a difficulty readjustment.  I'd bring it online in the hours _after_ said adjustment.  And then probably take it offline as soon as the difficulty readjusted to my cluster. 

Of course, that'd probably kill bitcoin, but only eventually.