Does bitcoind ERROR “Disk space is too low!” refer to RAM or actual harddrive?

After having finished the “Initial Block Download” I needed to reindex: [BTC_Core_Expmnt]# bitcoind -reindex -datadir=/mnt/BTC_Core_Expmnt The debug.log showed everything starting up ok; and the process beginning: [2020-01-20T07:43:41Z Loaded 119369 blocks from external file in 6005ms\ 2020-01-20T07:43:41Z Reindexing block file blk00001.dat…] Then a while later this: [2020-01-20T09:05:59Z Reindexing finished] But bitcoind continued grinding on… Well then…

Payable function that returns value: when is this example practical?

To quote an example from a book: contract StockPriceOracle { uint quoteFee = 500; mapping (string => uint) private stockPrices; //… function getStockPrice(string _stockTicker) payable returns (uint _stockPrice) { if (msg.value == quoteFee) { //… _stockPrice = stockPrices[_stockTicker]; } else { revert(); } } } There’s a payable function that returns a value. Correct me…

Why the gas estimation of erc20 approve() change with executation?

The approve function code in my ERC20 contract is below: function approve(address _spender, uint256 _amount) public returns (bool success) { allowed[msg.sender][_spender] = _amount; Approval(msg.sender, _spender, _amount); return true; } I tested approval gas cost estimation for multiple times in Rinkeby testnet, found that the estimation results will change like bellow: Test configuration: Account1 approve account2…

Full Node Bigger Than Online Reports?

I am running a full node and I noticed that the amount of disk space it takes is larger than reports online. I use the command ./geth –syncmode full –rpcapi eth,web3,personal –rpc –rpcaddr 127.0.0.1. The results from looking at my .ethereum file is as follows: 4.0K .ethereum/keystore 109G .ethereum/geth/chaindata/ancient 504G .ethereum/geth/chaindata 11M .ethereum/geth/nodes 163M .ethereum/geth/ethash…

Listen to a solidity event from a smart contract function

I have the following event: event WaitingPlayer2(address indexed player2); Which I call through: function partecipateAsPlayer2(address player2) public{ emit WaitingPlayer2(player2); } Is it possible to wait in a smart contract function for that even to be fired? Like this: function startGame(address requiredPlayer2){ //get the WaitingPlayer2 event with requiredPlayer2 address }

Signing message with private key and verifying signer in smart contract

I have a smart contract that provides a message to sign and then validates the signer of the message. Something like: mapping(address => uint) public userNonce; function getSigner(bytes32 message, bytes32 r, bytes32 s, uint8 v) public pure returns (address) { bytes32 prefixedHash = keccak256(abi.encodePacked(“\x19Ethereum Signed Message:\n32”, message)); address signer = ecrecover(prefixedHash,v,r,s); return signer; } function…