Homework on Stale Blocks

Blockchain and Bitcoin 101
#221

What happens in the bitcoin network when two miners solve a block at the same time?
When two miners solve a block at the same time each block is propagated to nearby nodes, validated and appended to the chain. Once one of those blocks encounters the other already appended to the chain, the network yields to that longer chain and returns the late-arriving block to the mempool since it cannot be used. The late block contains an out-dated hash of prior transactions, since a block was added after the late block was composed. The previous block header in the late block is really the second to last (penultimate) block header (or even perhaps an earlier block header), which does not preserve the chain.

What is a stale block?
A stale block is one that contains an out-dated hash of the prior block which represents all prior transactions. It cannot be added to the chain since at least one block was added after the stale block was composed.

How do stale blocks occur?
Stale blocks are the result of race conditions in calculation and block propagation.
Randomness in the effect of nonce to yield a target hash value can occasionally out-pace the network’s ability to propagate and validate blocks. Variations in the network’s bandwidth also impact the ability to completely validate each block before introducing a new block.

Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
Confirmations push a transaction deeper and deeper into the blockchain, so that its immutable characteristic takes hold forming a solid basis for subsequent transactions.

#222
  1. When two miners solve a block at precisely the same time a a fork occurs, creating and spreading to the nodes 2 separated versions of the blockchain. One will become accepted as a new block and the other will become a stale or orphan block.
    Forks can be temporary, lasting for a few minutes, or can be a permanent split in the network creating two separate versions of the blockchain.
  2. A stale block is the block that got discarded back into the mempool for having the shortest chain after the temporary fork (when two miners solve the block at precisely the same time).
  3. After the temporary fork. They very successfully mined but but failed to be added to the blockchain because another block mined simultaneously had its chain extended first.
  4. It is recommended to wait for 6 confirmations to ensure your TX doesn’t fall on a stale or orphaned block.
#223
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    The blockchain splits into two versions.
  2. What is a stale block?
    A stale block is a valid block when it is firstly added to the blockchain but later got dropped and sent back to the mempool.
  3. How do stale blocks occur?
    The bitcoin blockchain will always go after the longest chain. Stale blocks occur when a certain block was added first but later got dropped due to lack of enough confirmations.
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Because the bitcoin blockchain will always go after the longest chain.
#224
  1. One group of nodes will carry around a blockchain with one block at the end and another group of nodes will carry around a blockchain with another block at the end.
  2. A stale block is a block out of the two that doesn’t end up in the final blockchain long term. The other blockchain gets mined faster and gets longer and ends up being the one that there is consessus about.
  3. stale blocks occur when two block are mined and broadcast to nodes at the same time. This doesn’t happen very often because of the 10 minute average mining time.
  4. Because the chance of a block being a stale block decreases the more block are being added after it.
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#225

  1. When two miners solve a block at the same time a fork will occur.

  2. A stale block is a block that was not confirmed and returned to the mempool.

  3. A stale block occurs because two miners mined a block at the same time creating a fork and, because the network will only accept the block which is in the blockchain with more proof of work, the one that belongs to the shortest blockchain is dropped and returns to the mempool.

  4. It is importante to wait for more than one block to be confirmed when sending or receiving a transaction to make sure that the block will not be dropped.

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#226

  1. One of these blocks is sent back to the mempool.

  2. A Stale block is a block that was on the blockchain at some point but was later dropped for a longer blockchain with more proof of work. Dropped meaning they were not confirmed transactions they were sent back to the mempool where they wait to be confirmed.

  3. Stale blocks occure because there are many miners in many regions so computers may not communicate fast enough so they all have the same data at all times but eventually they all agree on the same block every 10 minutes

  4. It is important to wait for 6 confirmations on the blockchain to make sure your transaction was not dropped and sent back to the mempool

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#227

  1. They both become a valid version of the blockchain, waiting for the miner of the next block to choose a version.

  2. The block that didn’t get chosen by the miner of the next block.

  3. A stale block occurs once the miner of the next block has decided which block to use. This is because the network always favours the longer blockchain, so the block is rejected, making it a stale block.

  4. If you only wait for one confirmation, it is possible that your transaction is inside of a block that is currently part of the blockchain but could become a stale block if there are other versions of the blockchain and that block doesn’t end up getting chosen.

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#228

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    The blocks will be spreading to the network, will create 2 possible chains, and the biggest chain , when a miner have a new block will go in one that we knew, and from this point the we have more pow and will be the true chain. Other chain will drop and all transactions will back to mempool. Its good have 5/6 confirmations to really confirmed a transaction.

  2. What is a stale block?
    Stale blocks are blocks that were on blockchain one time, but they drop because emerge another version of blockchain that is longer (+PoW)

  3. How do stale blocks occur?
    They occur because the blockchain is global, an we may have 2 miners our more with a valid block, nonce and finish the puzzle at the same time. Creating 2 versions , one will be dropt , creating a stale blocks.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Is important because we have the possibility of our transaction be im one stale block and it go again to the mempool

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#229

The blockchain will have 2 different versions of the ledger in circulation. However, only the version with the most proof of work will survive.

A stale block is a block that was part of the blockchain, but because it was in a weaker version(less proof of work than another) of the blockchain, so therefore it was dropped.

When you have 2 versions of the blockchain competing against each other, only the one with the most proof of work is accpeted, all others are dropped and all blocks contained in those that were dropped become ‘stale’.

It is possible that the block that contains your transaction could be in a version of the blockchain that will become stale.

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#230

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Which ever chain gets the a next block added to the chain 1st will be longest and that chain will win.

  2. What is a stale block?
    A stale block is a block that was dropped from the network.

  3. How do stale blocks occur?
    When a two miners miner A and miner B, for example, create blocks at the same time and another miner C - adds a block to miner A’s BC , miner B’s chain is dropped causing B’s blocks to become orphaned or stale blocks.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction? It takes time for the longest chain to be propagated across the network so 6 transaction should give enough time to insure that your tx was not dropped do to it being on a stale blocks.

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#231

  1. Some of the nodes will adopt one of the miner’s blocks and the rest of the nodes will adopt the other’s, determined by their geographical proximity to each miner. Temporarily there will be two valid versions of the blockchain in existence.

  2. A stale block is one which was previously valid but had now been removed to resolve the issue of having more than one valid version of the blockchain at the same time. Its transactions are returned to the mempool.

  3. When two or more blocks are solved at the same time one of them will have a subsequent block added to it before the other. The block that has had a subsequent block added will be the one that is adopted by the network due to the greater proof of work. The removed block is defined as a stale block.

  4. Waiting for more than one block ensures that the block containing your transaction has been propagated throughout the network, agreed by the nodes and no longer at risk of becoming a stale block.

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#232

  • What happens in the bitcoin network when two miners solve a block at the same time?
    The block is propogated to the nodes closest to them in distance. The nodes for both blocks are validated. They need to be fast at guessing the Nonce or another block will come and be added to one of the current blocks producing a longer chain which will be chosen.

  • What is a stale block?
    A stale block or orphaned block is the remaining validated block that is eliminated and the transactions are sent back to the mempool

  • How do stale blocks occur?
    It is a validated block that is also a version of the truth but is not selected to be appended to the blockchain.

  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    6 block confirmations is recommended in case your block is dropped or becomes a stale block

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#233
  1. What happens in the bitcoin network when two miners solve a block at the same time?
  • two version of truth, blockchain splitting
  1. What is a stale block?
  • a droped block from the blockchain
  1. How do stale blocks occur?
  • When a new miner is basing his block on the other block from the split
  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
  • to reduce chans of blockchain split and stale blocks
#234
  1. When tow miners solve a block at the same time it will end up having two block chains. However, the next miner will choose which block to append while the other one is drop back to mempool and the blockchain will always accept the longest one.

2.The stale block is also known as orphaned block that is drop from the blockchain.

  1. The stale block occurs when two competing miners solve a block together and added their blocks to the chain but then only one is accepted when the next miner comes along and choose to continue on. Which means the miners are producing at the faster rate before the network synchronize together at a usual 10 minutest block time period.

  2. It is better to wait for one block to be confirmed in order to make sure your transaction is being added to the block chain but not dropped but eventually it will be mined.

E.g I bought some bitcoin from an ATM a while a go and it that takes me about 18 hours before I received but I knew it will come. Now I wonder how many times has been dropped? Still better than using international wire transfer… :pleading_face:

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#235
  1. The chain splits
  2. A block that was canceled
  3. When there is a split in the chain the longer chain remains and the other block become a stale block
  4. Because you want to know that your transaction is in a block that stay in the block chain. But I didn’t really understand why it meters… If it is in the mempool then it will be confirmed later…
#236

1- Both blocks are added to the Blockchain

2/3- A block that was created simultaneously with another block but was dropped because the other block continued on first

4- In case a stale block is found, the blockchain has time to add TX’s into a new block up the chain.

#237
  1. Assume 2 different miners solve the puzzle at the same instant. This creates 2 chains on the same length.

Now, let’s say that there’s a 3rd. miner looking to append his block to the blockchain. Depending on which one of the previous 2 chains he wants to propagate, the chain where he decides to add his block then becomes the longer chain. Since the longest chain is always recognized, the block on the shorter chain will then drop off the chain and all those transactions in that rejected block will be returned to the mempool.
2. That rejected block is called a stale block. Some call it a orphaned block.
3. The answer to this question is included in #1 above. However, another scenario under which stale blocks occur if when too many blocks are being mined at the same time i.e. when the degree of difficult is low. This is one of the reasons why the block reward time is kept to 10 minutes - not more, not less.
4. Waiting for 6 more blocks to be added to the chain is then considered safe to say that the appended block has been confirmed and is now part of the blockchain.

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#238
  1. When two miners solve the block a the same time, then the miner with more network connections to the bitcoin network or other criteria will get accepted by first. One will become accepted by the network and the other will be discarded.
  2. Stale Block is the block that is no longer part of the current best blockchain because it was overridden by a longer chain.
  3. Stale blocks occur when miners solve the same block at the same time, but often on other ends of the globe. Geographically closer nodes will pick up the block that was mined near them resulting in a small fork in the chain. However, the longest chain will be pick up as the best blockchain during 10 minutes block time.
  4. Because the block that contains the transaction may get dropped from the chain and all data in it becomes invalid. The best practice is to wait for 6 confirmations, to make sure that the transaction was valid.
#239

What happens in the bitcoin network when two miners solve a block at the same time?
Only one of them can win and eventually it will be the longest chain and the other is dropped.

  • What is a stale block?
    A stale block is the block that is in the shortest chain and therefore dropped.
  • How do stale blocks occur?
    Stale blocks occur when two miners produce a valid block at the same time but it has not yet received enough confirmations by the network. It has been propogated by some nodes and a different block is also on the network at the same time.
  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Because you need to wait to check that your block has been accepted on the network and the longer the block chain then the more likely it is to the best version of the truth on the network.
#240
  1. Blockchain forks temporarily
  2. It is a dropped block
  3. When the longest chain has been chosen
    4.to make sure that a transaction is not lost with a stale block
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