Tom van der Woerdt
  • Member for 8 years, 9 months
  • Last seen more than 4 years ago
How useful is a JavaScript miner?
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33 votes

Javascript has access to OpenGL ES, including shaders, so it has access to programmable parts of the GPU at nearly native speeds. I think that a smart kid might be able to build a fragment shader that ...

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Do unconfirmed transactions expire?
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29 votes

Most clients on the network have a transaction pool in their memory. The same basically applies to miners: they just dump the top 500KB (or some other value) transactions into a block, sorted by ...

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Why do AMD's GPUs mine faster than Nvidia's?
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15 votes

Summary: different approach to calculations. Nvidia GPUs are more like CPUs, in that they have only a few processors that do work, but faster. ATI GPUs have slower processors, but a lot more of them. ...

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When a transaction is broadcast to the network, what is actually being sent?
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10 votes

Client creates a new transaction, adds it to its memory pool Client broadcasts an inv frame, which indicates that it has something in its memory pool, by giving the hash of the transaction to one or ...

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How to install a Bitcoin client on Ubuntu Server
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9 votes

Once you've installed bitcoind, you should create a configuration file (stored in ~/.bitcoin/bitcoin.conf) containing at least an RPC username and password, and then you just run bitcoind to start the ...

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How much energy will the Bitcoin network eventually consume?
7 votes

The upper boundary for energy usage can be described with a function of the profit and energy costs. Miners won't ever pay more for energy than they get from profits. The actual energy usage formula ...

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DDoS on big mining pools: a quick way to 51%?
7 votes

There's no cooperation involved in mining, and they won't be trying the same hashes because (for example) they have different transaction pools and (possibly) different destination addresses. Mining ...

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Can the outputs of transactions with duplicate hashes be spent?
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6 votes

Updated as my earlier answer was wrong Quoting from BIP 0030: Blocks are not allowed to contain a transaction whose identifier matches that of an earlier, not-fully-spent transaction in the same ...

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What is the hash-rate of the Bitcoin network that results in the maximum difficulty?
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6 votes

The hardest possible target is all zeros plus a one (0000000...1). If such a block were ever mined (which is extremely unlikely: on average you'd need 2^255 hashes per 10 minutes, which is 9.6e73 ...

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Creating my own bootstrap.dat?
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6 votes

The block files are in the same format as the bootstrap file. Their format is really simple: just concatenate all blocks after prefixing them by the network number (to avoid mixing the testnets) and ...

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Code modification could lower mining-difficulty requirements, why isn't this a vulnerability?
6 votes

Nothing (as long as nobody else changes that code as well). I could easily mine hundreds of blocks a second using modified code. However, as none of those blocks would be accepted by the rest of the ...

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How do you make a Genesis block?
6 votes

The genesis block is really nothing more than a block that doesn't have a previous block. Creating a new genesis block only involves setting the previous hash part of the block to all zeroes. Because ...

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Does my wallet need to be unlocked to mine?
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5 votes

No, it doesn't have to be. Mining doesn't require private keys, only (part of) the public one. Having only the address of the destination is enough, so the wallet can be locked.

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Will Flattr support Bitcoin?
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4 votes

Your timing is perfect. Yesterday Flattr announced that they were going to implement Bitcoin.

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How do you make a good choice of server host to run an exchange on?
4 votes

First of all, don't even consider using VPSes for these things. As long as there's a layer above the OS that can be hacked, the data cannot be safe. Also, if things are going to be safe, you're going ...

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How do I create the coinbase from the genesis block?
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4 votes

The nBits don't exactly get swapped. The notation on the wiki is in big-endian notation, which is basically the notation you'd use when displaying it, similar how the number twelve is written 12 and ...

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Do I need to wait for Bitcoin-Qt to sync with the network before using GUIMiner?
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3 votes

The answer depends on whether you're using a pool to mine. If you use a pool to mine, you don't need Bitcoin-Qt to mine, so you can mine straight away. If you don't use a pool, you need Bitcoin-Qt to ...

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Do all private keys that are resolved to the same address give access to the bitcoins on this address?
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3 votes

Yes. And it's pretty easy to understand why, without even mentioning anything about the underlying technologies. A bitcoin: URL only contains the address of the recipient. The address does not need ...

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How does blockchain.info access my wallet in MyWallet
3 votes

Your wallet is only used to send coins. To receive coins you don't need access to the wallet.

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Is the time value in transaction or block information the time it arrived at my client?
3 votes

Blocks have timestamps, transactions don't. The time of a block creation is known, the time of the transaction can only be guessed. Most clients use the block's time for transactions, and if they're ...

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How do I go about installing a Bitcoin daemon in CentOS Linux?
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3 votes

I host two bitcoind RPMs (i686, x86_64) on my website which will most likely work fine for you, as they're built for CentOS 6.4. Run this command to install bitcoind : rpm -ivh http://tvdw.eu/bitcoin-...

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Transaction broadcasts and block synchronization
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3 votes

While implementation specific, transactions are only re-broadcasted by the bitcoin-qt client after every x minutes (30?) and only if it's not in the main chain yet. Once a block comes in that has the ...

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An explanation of transaction scripts
3 votes

Scripts are used to determine the person who can spend the transaction (at Bitcoin you spend using transactions, not using BTC on an address). To understand scripts, you probably first need to ...

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Is there a way to estimate total number of bitcoin users/wallets?
3 votes

The number of wallets is impossible to count, as they can contain zero to thousands of addresses each (zero, as there may be users who just want to observe, or clients that only create addresses when ...

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How do I compute merkle root for genesis block?
3 votes

Instead of looking at the source code, take a look at the relevant wiki page. As blockexplorer will reveal, the merkle root of the genesis block is equal to the hash of the transaction in it. This is ...

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How much time does it take for the bitcoin-qt window to show up in OS X 10.4?
2 votes

When you open the Mac client, it first displays the loading screen for a while : After that it displays the main screen and starts synchronizing : Note that the client is really slow and might take ...

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given a json of a block, how do I calculate its hash?
2 votes

As described on the wiki page about block hashing, the 2xSHA256 hash is taken of the block's header only (not the transactions in it): 80 bytes, consisting of the version, previous block hash, tx ...

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How long should synchronizing your wallet for the first time take?
1 votes

It downloads roughly 7GB of data, so it will take a very long time via mobile internet. For desktop computers via normal internet it usually takes roughly a day.

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How to read the transaction pages on blockchain.info?
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1 votes

Change for a transaction doesn't have to go back to the original address: part of it can be sent to the receiver, and the other part can go back to a new address. That way it's slightly harder to ...

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blockchain.info: "No operations allowed after connection closed."
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1 votes

A few minutes ago they restarted the servers, and they won't allow you to make transactions while they're not connected to the network. Since a restart implies a temporary disconnect, you just have to ...

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