Questions tagged [blocks]

This tag is for questions dealing with the structure of blocks.

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1answer
151 views

how blockchain-cloud companies like Storj prevent changing files by farmers? [closed]

How does companies like Storj handle the possible situation of farmers who can change the files that they store? Say I upload to the blockchain cloud network the file "cat.jpg". Now a contract added ...
5
votes
1answer
414 views

What are the mechanisms that use the Ethereum network to decide when a block B is done and we are going to mine block B+1?

I know from the Ethereum Stats that a block is mined on average within 14 secs. But that is only on average. I want to know, step by step if possible, what are he mechanisms to say "okay, this block ...
4
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0answers
74 views

Will forthcoming ability to make transactions private hide gas usage and mining information?

I understand that people are working on allowing for more private transactions on the public Ethereum mainnet. This would involve hiding (at the very least) the from, to, value and probably input ...
1
vote
1answer
634 views

How are the blocks traversed?

How are the blocks traversed? Is it using a linked list concept to traverse? If I need to see all block details, will it traverse from the genesis block to the requested block or will it traverse ...
2
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1answer
900 views

Calculate approximative block height at a certain time?

What would be a formula for calculating the block height at a certain point in time, approximative How would I calculate the block height for a date like next Christmas 0h midnight?
5
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2answers
4k views

What does every field in block means

Can you give a detailed description for every field in Ethereum's block structure? For example: > eth.getBlock(123) { author: "0xbb7b8287f3f0a933474a79eae42cbca977791171", difficulty: ...
1
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0answers
73 views

Can a contract know about other transactions in the same block as one of its own? [duplicate]

I've read that transactions in the same block that call the same contract will execute in an arbitrary order if sent from different accounts. My question is, for any given transaction that may be ...
2
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2answers
409 views

Why doesn't ethereum have a fast relay network like Bitcoin?

I'm talking about nodes that miners connect to that help relay blocks fast, to reduce hash power wastage and forks: http://bitcoinrelaynetwork.org/ and http://www.falcon-net.org/
1
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1answer
127 views

logically centralized but physically decentralized contract

Reading https://uport.me/library/pdf/whitepaper.pdf it states : The uPort Registry Contract acts as a logically centralized but physically decentralized registry or lookup table mapping each uPort ...
1
vote
1answer
5k views

Is there a way to recover ETH with Account Number and Password Only?

I have 1 ETH in an Ethereum Wallet. I would like to transfer it, but I am unable to get the wallet functions to work due to another issue. (Mist not recognizing my 1 ETH) I know the wallet address and ...
3
votes
2answers
215 views

Transaction not performed, morden.ether.camp has different transactions than me (Morden)

I'm on morden network. I received Ether and waited roughly one hour, but I have > web3.eth.getBalance("0x3061c735f4e9172a3c66d07fcde6ea560bb3369c") 0 However, the transaction is confirmed: https:...
1
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1answer
350 views

How many blocks are created at one point of time?

How many blocks are created at one point of time? Can miners create a block? If Yes, then how can we stop the same transaction to be entered in two different block?
3
votes
1answer
892 views

How does Ethereum avoid inaccurate timestamps in blocks?

A contract can reference the currently being mined contract's timestamp. This means that changing the timestamp of an in-progress to be mined block requires executing all contracts referencing that ...
8
votes
1answer
2k views

What action would actually lead to an invalid block and what happens to the valid transactions in that block

I'm trying to figure out how an invalid block would come into existence and what happens (technically) to valid transactions in the invalid block. From what I understand, invalid transactions (like ...
20
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3answers
4k views

Why does ethereum creates a new block,without even a single transaction? [duplicate]

I'm running a private Ethereum blockchain. When I set one of the nodes to mine, that node continuously creates blocks, even if there are no transactions inside of it. What is the purpose of this?
2
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1answer
686 views

Can I call contract function (balanceOf) based on block number?

I want to check the DAO balance address in the specify time(block number) Is it possible to specify the block number when calling a contract function in web3. var contract = web3.eth.contract(abi)....
6
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2answers
2k views

Blocks are not being downloaded [duplicate]

After the attacks the clients are shit. At the moment, I am unable to download any blocks, except if I delete all the chaindata and it starts again. I have less than 6k blocks left to download and I ...
4
votes
1answer
6k views

How to speed up transaction confirmation time?

I recently ran some tests on one of my testnet nodes and found out that my average transaction takes between 30 seconds to 2 minutes to confirm, despite the block times being at around 15 seconds. I ...
4
votes
1answer
134 views

Should uncles factor into average network block time and difficulty calculations?

It's unclear to me if uncles should factor into averages like block time and difficulty. The fact that they are associated with a parent block and have a timestamp and difficulty, leads me to believe ...
4
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2answers
843 views

what is the logic behind rewarding 5 ETH for mining a block?

Is it in someway related to the transaction cost charged by ethereum for each transaction ?
11
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3answers
27k views

Storing document/file in blockchain [duplicate]

I am planning to do a POC on blockchain for uploading and verifying documents. I was wondering if I can store a complete document in blockchain. After some research on net most of the example, I found ...
18
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1answer
6k views

Are gas limit in transaction and block gas limit different?

What does gas limit mean? Are there two meanings of gas limit? gas limit in a transaction block gas limit
8
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2answers
4k views

Difficulty and total difficulty

This is the info of one of the blocks in my private blockchain: { difficulty: 759585, extraData: "0xd783010409844765746887676f312e362e32856c696e7578", gasLimit: 4712388, gasUsed: 0, hash: "...
5
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1answer
4k views

How to use blockchain as a Database?

I'm pretty new to the concept of blockchain and use cases so please bear with me if this sounds to vague or elementary. As, I researched more on this, I wanna know how can we use blockchain as a ...
9
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2answers
12k views

What is the exact data structure of each block?

is there any document / diagram describing Ethereum block structure in similar way as https://en.bitcoin.it/wiki/Block? I know I can find implementation at https://github.com/ethereum/pyethereum/...
2
votes
1answer
231 views

What happens if a miner who didn't soft fork mines an “invalid” block?

Can someone explain, technically, what would happen if a majority of the miners adopted a soft fork (forward-compatible) making some tx invalid and then a miner who didn't fork happened to mine a ...
18
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3answers
4k views

What is the default ordering of transactions during mining, in e.g. geth?

I know that the yellow paper does not specify how transactions are to be ordered in a block and this is up to the miner to decide. But I am interested in how this is practically handled (I assume not ...
10
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2answers
2k views

What does it mean to “seal a block”?

In both the Ethereum chain specification format and in Parity's documents on private chains, you see the term seal a block. What exactly does that term mean? How is it different than mining a block?...
15
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1answer
4k views

Relationship between Transaction Trie and Receipts Trie

Reading through the Yellow paper, I can see that each block header includes the Keccak 256 hash of the root of the trie for transactions and transaction receipts. I am struggling to understand how and ...
7
votes
1answer
293 views

Can you (as a node) manually choose what block to bet on in Casper?

Ethereum plans to move to the Casper proof of stake algorithm in a future version of the network. However, as nodes are betting on which block will be produced next, does that mean (as a node) you can ...
8
votes
1answer
384 views

Does more ether = more voting power in Casper?

Ethereum plans to move to the Casper proof of stake algorithm in a future version of the network. However, as nodes are betting on which block will be produced next, does that mean the more ether you ...
4
votes
1answer
442 views

Is block's timestamp current block's or previous block's timestamp?

When I call function giveTime, is the time stamp "now" from the block where my call is mined or from the previous block? contract Time { uint time; function giveTime() { time=now; } ...
2
votes
0answers
121 views

Blockchain taking abnormally long time to download? [duplicate]

I'm a newbie to Ethereum. I initialized the download process for the Ethereum network blockchain using geth yesterday (geth --rpc). It's been nearly 20 hours and blocks are still being imported. Is ...
5
votes
1answer
778 views

How does mining software choose transactions?

How does mining software choose transactions from a memory pool to include them in a block? Does mining software just include transactions in order each time it receives them? Or they choose ...
4
votes
1answer
89 views

Is there a way to force uncle blocks generation in a testnet?

In a local testnet, what could be done to force uncle blocks generation? I'm mining with multiple geth instances (different accounts) on a common CPU and very low difficulty genesis block.
8
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2answers
2k views

How do I know if a submitted block became an uncle?

We need to detect that the submitted work became an uncle. How would I do this with geth api? I thought of checking the submitted block number later for any uncles that match my block's hash. Is there ...
16
votes
2answers
2k views

What happens when a smart contract gets several similar calls in the same block?

What happens when a smart contract gets several similar calls in the same block? Consider for instance this greeter: contract greeter { string name; function setName(string name_) { ...
3
votes
1answer
117 views

How to edit starting parameters of the genesis block in mix?

When I click the "import" button it seems to want to import stuff from a file. But what structure etc should the file have? Cannot find any documentation on this. Any pointers gratefully received.
6
votes
1answer
821 views

How are block proposals made in Casper?

A blog post says this about block proposals in Casper: A NXT-style random number generator is used to determine who can generate a block at each height; essentially, this involves taking missing ...
20
votes
2answers
4k views

Why are there no leading zeroes in ethereum block hash?

The block hash has to be below certain difficulty, right? In bitcoin this means, that there are many leading zeroes in hash value, eg. for bitcoin block #402329 hash is ...
37
votes
3answers
64k views

How to delete or reset the blockchain in geth? (OSX)

I have a currupt Blockchain and want to hard reset the chain. what do I need to delete in order to start downloading the chain from scratch? I know that there are 2 ethereum folders (I am on OSX): $...
14
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3answers
2k views

How to parse blocks with Python?

I'm building a basic analytics framework for the Ethereum blockchain. As a first step I need to extract the data and I'd like to do this in Python. I've been using Geth as a client on OSX and so, as ...
12
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4answers
7k views

How can I get the data of the latest 10 blocks via web3.js?

How can I get latest 10 block data by using web3.js like most block explorer does?
4
votes
1answer
19k views

How long does it take for the ethereum blockchain to synchronize? [duplicate]

For the past few days I've been synchronizing my mist wallet with the blockchain (using geth). My laptop has been working all day and all night. I've already synced more than 880000 blocks. How many ...
40
votes
2answers
22k views

Is there a limit for transaction size?

Is there a theoretical limit for transaction data size when you send a transaction to Ethereum network? Ref. Is there a (theoretical) limit for amount of data that a contract can store?
1
vote
2answers
944 views

What is the full block reward? [duplicate]

The Ethereum launch process states that with the release of Homestead, the Ether mining will be at 100% rather than 10% of the usual reward rate. Does that mean the full block reward would be 50 ...
-1
votes
1answer
326 views

What capacity is ethereum using recently?

What capacity is ethereum using recently? How many more people can use ethereum now? What is current blocksize, and what are all the data being broadcasted between nodes? I read that ethereum just ...
63
votes
1answer
10k views

Why is the average block time 17 seconds?

The network stats show a constant average blocktime of around 17 seconds. Whenever you check it is around 16~18 seconds. Reading the blog post by vitalik buterin it states the block time should be 12 ...