10

reindex doesn't also re-validate blocks, does it? It does, but signature verification (the slowest bit) is skipped on most of the early blockchain. The command attempts to sync with the network by reusing as many blocks as possible that are already written to the disk, which may very well include damaged or partially written ones. Any experience with ...


9

Pass -dbcache=N as a command line option. N is a number in megabytes, and setting it higher significantly improves verification speed. The default is 450, but up to 6000 or so you can notice improvements. This is superior to using a RAM drive.


8

"Bitcoin-Qt/bitcoind version 0.7.1 and later supports a special import feature: If the file "bootstrap.dat" is found in the bitcoin data directory, it will validate and import all blockchain data found in that file." The official torrent can be found at: http://sourceforge.net/projects/bitcoin/files/Bitcoin/blockchain/ Magnetic link: magnet:?xt=urn:btih:...


7

More threads will not make your software run faster. Threads are used in order to be able to do more things concurrently, but not necessarily faster overall. Assume your internet connection allows you to download at 1 MiB/s, and you want to download 5 files of 200 MiB each. No matter what, you need to download 1000 MiB, which will take 1000 seconds. But you ...


7

The throughput in Bitcoin is not defined in transactions per second, rather indirectly, via block size limit. What matters in the size of transactions in bytes. The more complex the transaction is (complex meaning more inputs and outputs, long scripts), the more space it takes. A typical full (nearly 1 MB) block in Bitcoin includes around 2000 transactions, ...


4

Both are implementations of the Bitcoin protocol, however they are customized to make it easier to develop with. They are able to do this by storing all transaction and blockchain data in a database for quick queries, and along with this comes large disk space requirements (200-300GB). Bitcore (I have used) - NodeJS - 200+GB required for storage as it ...


4

With the advent of ASICs, Bitcoin GPU mining is no longer profitable. I would recommend mining a Scrypt coin such as Dogecoin or Litecoin. (You can then trade it in for Bitcoin on an exchange, if you prefer.) To answer your original question, yes, you can use one card for mining and the other for actually running the computer.


4

SHA256 uses a compression function that maps a 64 byte input block and a 32 byte chaining state to the next chaining state. It divides the message into 64 byte blocks and hashes those sequentially. The bitcoin proof of work uses SHA256(SHA256(block_header)). Between each hashing attempt only 4 bytes in the last block of the header change, so for each ...


3

I know people tend to get obsessed about the confirmation time, but the important factors are the number of nodes and the speed at which any given transaction is seen by the network as a whole. I believe this is under three seconds for a transaction to be seen by the entire bitcoin network. Why is this measure important? Because this is the so-called "...


3

Bootstrapping will be deprecated as of the 0.10 release in a few weeks. The torrent file mentioned in other answers will never be updated again because it is faster to have Bitcoin Core sync over the network. So no need to download the Blockchain seperately anymore! You can find the release notes here https://github.com/bitcoin/bitcoin/blob/0.10/doc/...


2

The bulk of the work lies in verifying each transaction within the block. This means that the signatures need to be checked for each transaction input, which requires a lot of CPU processing. So, one way to improve the verification speed would be to have a hardware-assist for the verification process (such as a specialized ASIC chip). I don't know if a ...


2

There's a difference between a software thread and a CPU thread. The number of threads that you are seeing is not the number of CPU threads that bitcoind is using. It is the number of software threads that it has created, which are different from CPU threads. You can't make the software create more software threads; that's not possible and not how the ...


2

The balance is calculated from something called UTXO, this is a list of unspent coins, it is created on blockchain rescans and updated on receiving of new blocks. It is therefore not dependent on transaction history size but only all current available coins fragmentation. There are performance issues with this solution also, but they are been worked on...


2

All numeric values on the wire are little-endian with the exception of network addresses and ports, which are big-endian. This includes Sha-256 digests which are treated as 32-byte numbers. It does not include data pushed on to the script stack, however, which is copied as-is from the script element. The regular numbers aren't really a problem since you ...


2

Connecting to more nodes will not make you learn about transactions faster, after some point. Your node will just be busy processing messages - including many uninteresting ones - to maintain connections with all peers, making it slower at processing new things. Connect to a few fast peers with -addnode, or even run multiple nodes yourself, and ...


2

Bitcoin Core maintains an index of blocks and their locations on disk. When someone requests a block, it pulls the block from disk, and if they used BIP 37, it will run the block through the filter. The block index is required for normal node operation; there are no other indexes created. The only "index" like thing is the mempool, and that is maintained ...


2

I don't know how well it performs, but here is a full node implementation of Bitcoin in go-lang that you could investigate: https://github.com/btcsuite/btcd


1

I mean, is there a way to import the real bitcoin transactions on the blockchain into a private blockchain? no


1

USB stick ASIC mining devices often fail due to lack of power over the USB port: laptop USB, weak USB hub, weak power supply. Make sure you use a powered USB hub that others have had success with. Not all powered USB hubs can handle bitcoin mining. This is especially problematic when running multiple USB sticks, but even a single stick can fail if your USB ...


1

The behavior I noticed from a reindex on my node was that it ended up reloading the entire blockchain from the Internet. This is consistent with what the Bitcoin Meister Pieter Wuille indicated. Will have to remember the dbcache trick...


1

What you read is not accurate. There is no significant difference in mining performance depending on your location. First of all, as far as I know, the vast majority of miners run their equipment 24 hours a day (since leaving them idle just wastes the investment in hardware), so time zone differences are irrelevant. Also, to first order, your chances of ...


1

The transaction verification process is not particularly CPU or memory intensive. The CPU intensive part is the network protocol needed to get a global consensus on a single total order of transactions. That is called "mining" and that is what the specialized ASICs from various companies such as kncminer are designed to help with.


1

The general answer is that your card replacement caused the huge drop in hash-rate. Radeon cards are generally better for mining (faster and more efficient) compared to Nvidia. There is a nice chart that approximates hash rate per card here: https://litecoin.info/Mining_hardware_comparison You should really consider mining scrypt algorithm at either a ...


1

Unfortunately by design, each scriptSig is verified slightly differently, so a different sig is required to redeem each input.


1

Yes you can I use a gtx 460 (as the main card) and r9 280x as alt coin mining card. (bitcoins... ha ha impossible) Just install amd drivers for the mining card, and use a dummy plug with the r9. also some cgminer special commands are needed in order to make it work nicely..try googling a lot until you find the answer for the cgminer command line... can'...


1

I'm pretty sure both cards have to be the same make and model for your motherboard to recognize them so that both would work at the same time.


1

I have written tools that an auditor should find very helpful for this purpose. The tool scans both receive and change addresses up to the gap limit, which is 20 by default (matches the standard), but can be adjusted if wished. The steps can be as simple as: obtain the Master XPub key for the wallet. Go here to find all the addresses that have ever been ...


1

Do they need to pre-generate a list of all possible public keys and watch new blocks for those transactions? Essentially. Assuming that there is no limit to BIP32 keys, that means the auditor would need an infinite amount of resources to audit a key (pre generation, and then cross referencing each incoming Tx). What are some appropriate ways to ...


1

The calculation of the balance of a public address is not part of transaction validation. In order for a transaction to be considered valid, it must redeem unspent transaction outputs. Transaction outputs are always redeemed entirely, so there is no need to calculate the balance of a public address, only to check that these outputs have not been redeemed (...


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