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6
votes
1answer
815 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 ...
8
votes
2answers
2k views

contract event not firing in web3 node console

It appears my events are not being fired in my node application when I transact the contract in the ethereum wallet gui. I deployed a custom contract via ethereum-wallet I have fired up geth attach ...
8
votes
1answer
13k views

Error: Invalid JSON RPC response: undefined from node web3.js app

I'm getting Error: Invalid JSON RPC response: undefined from my node.js application when it tries to execute a function. My steps: ethereum wallet 0.5.1 to deploy a contract to the testnet. start the ...
7
votes
1answer
2k views

How can I do a fast geth sync without consuming too much memory?

My problem is this. The recommended advice in order for geth to run a faster initial sync is to use the option --fast plus a non-default value for the option --cache. The option --cache appears to be ...
5
votes
1answer
323 views

Is the transaction fee reduced from the transaction value?

Address A holds 1 ether and address B holds 0 ethers. Lets create a transaction to transfer all balance from A to B. This transaction will consume roughly gas_price * gas_used = 20 gwei * 21000 = 0....
20
votes
2answers
3k 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 ...
13
votes
1answer
3k views

How to make external contract function calls from one contract to another?

I'm having a hard time understanding the documentation for making an external function call from one contract to another. In this tutorial there is an example: contract InfoFeed { function info() ...
4
votes
1answer
844 views

Why does web3.js throw anonymous errors and swallow errors?

web3.js throws a lot of errors with no stack trace, making it hard to debug. for example: ./node_modules/web3/lib/web3/formatters.js: throw 'invalid address'; ./node_modules/web3/dist/web3-...
5
votes
1answer
1k views

Is it possible to calculate the gas costs of a transaction exactly upfront?

In the Ethereum wallet there are the estimated gas costs. Why is it only an estimate? Is is possible to calculate the gas costs precisely upfront?
31
votes
8answers
13k views

What are the development tools for Ethereum?

Could someone make a list with development tools for Ethereum together with a short description what they are good for?
6
votes
1answer
859 views

Not enough components (4) in value to assign all variables (6)

This is an exception on compilation I am getting with truffle. The code I am running builds a store from a container contract and then makes a call to get a product from it. Store s = Store(saddress)...
3
votes
1answer
757 views

How to read responses from calls to contract methods made using web3.js?

I have built a contract which provides a simple method for storing some data in a property of my contract on the blockchain. I can interface with my contract using web3.js and I have no issue doing ...
2
votes
3answers
3k views

How to update Geth on Ubuntu without using the PPA

I originally downloaded Geth using the instructions on the original (read: old) Ethereum homepage, using a curl command in a Bash one-liner. I now want to update to a version that will support ...
2
votes
1answer
314 views

cpp-ethereum (Homestead) starts resyncing blockchain

I just installed cpp-ethereum 1.2.2 in order to upgrade to Homestead. When eth is started it begins to re-sync the blockchain from block 1, while the whole blockchain is already on my machine. Is ...
10
votes
2answers
3k views

Is it possible to call Ethereum API from a Software Application without running an ETH node?

I was wondering if it's possible to make a call to Ethereum blockchain from a software application on my computer without having to run an ethereum node ? for example, I want to make calls from a ...
3
votes
1answer
169 views

Where could I find the program logic of contract in the blockchain of ethereum in Mix?

I am trying the tutorial scenario of Mix (https://github.com/ethereum/wiki/wiki/Mix:-The-DApp-IDE) for the first time and have a question here. After I deployed the rating contract, where could I ...
5
votes
1answer
492 views

Can't estimate gas usage in Mist 0.5.2

Since I upgraded to Mist 0.5.2, I get this when trying to transfer funds: We can't estimate your gas usage properly, as you need at least 1 ether in your account My account has 3 ethers.
38
votes
2answers
28k views

Is Ethereum wallet address case sensitive?

I sent some amount of ETH to a wallet. I checked the wallets balance on ether chain. I entered the address in the search field and noticed both lowercase and uppercase versions of the address seemed ...
4
votes
1answer
76 views

Until when can I safely broadcast transactions before homestead?

I would like to broadcast a transaction. When should I "hold" and let the homestead release happen? Until when can I send transactions?
23
votes
4answers
16k views

How can I empty the blockchain?

I am trying to do a fast sync using geth --fast but I am getting this message: blockchain not empty, fast sync disabled How can I empty the blockchain to allow for fast sync?
5
votes
1answer
1k views

testnet mining extremely slow

I'm trying to run a private testnet (OSX, geth v1.3.5) but finding that mining is either not starting properly or is extremely slow. I am using a custom genesis json as follows: { "nonce": "...
8
votes
3answers
5k views

CPU mining JSON_PARSE_ERROR

I just wanted to mine ETH with my CPU. I use Windows 7 64 Bit with ethminer. I started the cpu miner with a batch ethminer -t 6 -C -F http://ethereumpool.co/?miner=5@0x17C0Bea7c44*******...
2
votes
1answer
351 views

Geth Sent the Transaction to the Wrong Address?

I just followed the guide, and I made the same mistake as someone else, found here. Essentially if you use the syntax to:eth.accounts[0xXXXXXX....] instead of to:"0xXXXXXX....", Geth will create its ...
5
votes
1answer
796 views

Why does Solidity need modifiers?

Is there any reason for why Solidity has modifiers instead of just having a normal function which is called in the first line of a function body? The docs motivate it with readability but I do not see ...
2
votes
0answers
51 views

Mix doesn't render browser window - “unable to resolve the server's DNS address”

I am trying to do the Mix getRating tutorial from GitHub. After I enter the solidity code and the html code, the Mix status bar indicates that it compiled successfully. However, the browser windows ...
8
votes
3answers
4k views

Mining ETH on HD 6950 DAG allocation problem

I have 2 HD6950's which I wanted to use for ETH mining - but I have the well known DAG allocation problem. I can't find a solution for this problem - that's why I'm asking here. And please don't tell ...
30
votes
5answers
18k views

How to access the event log by knowing the contract address (web3)?

How can I access a log stored in one of the tx of the contract via web3? Code example: event newtest(string indexed name, uint indexed idlevel,string indexed multib, string objmulti, uint objnm); ...
3
votes
1answer
220 views

How do I reference a certain structure

Here are my declarations and code: struct Key { bytes32 blindedKey; uint deposit; address player; bool revealed; } mapping(address => Key[]) public keys; function seating(bytes32 ...
4
votes
2answers
163 views

When a bonded node loses a bet who gets the ETH?

In Casper Proof-of-Stake, a validator needs to be a bonded node: it puts up a security deposit that can be lost if the validator misbehaves. When a bonded node misbehaves, who receives the lost ETH?
1
vote
1answer
603 views

“code”:-32600,“message”:“Could not decode request”

I am trying to send requests to the jsonrpc server as instructed in this link https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getblocktransactioncountbynumber The command works fine in the ...
6
votes
2answers
8k views

How to fork my own version of ETH?

I would like to understand the basics of Ethereum and i would like to clone it and make my own local currency based on Ethereum to experiment at most its capabilities. Is there anyone that can give me ...
2
votes
1answer
429 views

Pass an array along when a contract creates a new contract

Can an array be passed along as a contract creates a new contract ? Specifically, an array of addresses. address[] verifiedUsers; new generatePOItokens(verifiedUsers);
2
votes
1answer
878 views

Have key store file and password - how can I access my ETH without Mist/Geth

Maybe a Noob question. I have the text file from the keystore folder. I have the password. How can I access my funds without using Mist/Geth? These are not working on my computer. Is there an online ...
2
votes
1answer
851 views

Possible to make a REST call within geth console?

I want to listen to events on a contract and then send them to a rest endpoint. Is it possible to make a REST call within the geth console? Alternatively, if I have a node application and I load web3,...
5
votes
1answer
133 views

Using strings in a Serpent contract

In the limited documentation on Serpent, it mentions the ability to use a str type as both input and output to a contract function. Short strings are converted to numbers and longer text uses the ...
3
votes
2answers
261 views

Developing a lisp(y) contract language

While it would not be possible to implement everything, could it be useful for domain specific applications to have a lisp based contract language that implements a certain subset of features? ...
4
votes
1answer
844 views

Hash Test: How to produce hash output

Here is a basic hash test. I am trying to reproduce the output with: http://emn178.github.io/online-tools/sha3_256.html Is sha3-256 correct? The output for '1' as the value input is ...
2
votes
1answer
79 views

Contracts with custom fee and limited numbers of transactions

Is there a valid way to set custom re-sell fee for "custom currency", e.g. https://blog.ethereum.org/2015/12/03/how-to-build-your-own-cryptocurrency/ and limit this re-sells somehow? For example: 0. ...
72
votes
5answers
117k views

What actually is a DAG?

I have tried googling it as well as finding it here. Many people here talk about it, but what actually is a DAG?
4
votes
1answer
230 views

Importing paper wallet using geth gives encoding error

Importing from a paper wallet(myetherwallet) gives: Could not create the account: encoding/hex: invalid byte: U+007B '{' I am using the private unencrypted key. go 1.5.3, Geth 1.3.5, Waller 0.5.1,
27
votes
2answers
16k views

What is the ethereum transaction data structure?

I'd like to know the detail of the Ethereum transaction data structure. What data is stored in transaction?
5
votes
2answers
729 views

web3.eth.getCode executes weirdly

I am trying to get a contract code from javascript. However, when I run this: web3.eth.getCode("0x9bA082240DBa3F9ef90038b9357649Fa569fd763") on my browser console, I get an Invalid address error ...
2
votes
1answer
2k views

IF statements in Solidity not behaving as expected

When I fire this function for the first time it seems revealEnd = now; fires because the reveal period ends. Yet revealCount does in fact display '1', indicating that we went into BOTH if statements. ...
15
votes
0answers
4k views

What is the difference between “geth” and “geth --fast”? [duplicate]

EDIT : I hadn't see the other question but this one ain't a duplicate because I'm asking here, precisely, if the state differs and if it does, what are the implications. The answer to that question ...
8
votes
4answers
2k views

web3.eth.getStorageAt for mapping

How can I get contract mapping storage? Considering this simple contract contract Currency{ mapping(address=>uint) public balances; function deposit(){ balances[tx.origin]++; } } ...
3
votes
1answer
508 views

What was the maximum password length of a pre-sale wallet/accounts?

What was the maximum password length for pre-sale wallets/accounts? While we're here, is there a maximum password length for accounts created now, using standard tools like geth/mist?
4
votes
2answers
417 views

Is it possible to obtain GENESIS transactions through RPC API?

When querying the genesis block via the RPC-API (of geth), no transactions are returned by eth_getBlockByNumber. eth_getTransactionByBlockNumberAndIndex similar fails to return any information. I ...
3
votes
2answers
2k views

How to upgrade my 0.3.7 wallet

So I have an old version of the mist wallet 0.3.7. How do I update it? I have a few hundred $ worth of coins in there and I don't want to lose them. I don't see any way to back up the wallet or ...
2
votes
0answers
165 views

Is there a blockchain explorer that allows me to see a contract's data? [duplicate]

I've looked at the three blockchain explorers available, but AFAICT none of them provide the ability to look at the contract's data. They only allow you to see the code. How can I examine a contract'...
19
votes
6answers
6k views

How to remove gas system from ethereum

I'm testing Ethereum with a complex contract which requires quite a lot of gas. And I'm testing (and will be running) a private network with controlled miners, so I don't need them getting any reward, ...

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