Homework on Stale Blocks

Blockchain and Bitcoin 101
#4635

  1. The chain will fork out.

  2. A successfully mined block not included in a current longest chain.

  3. They occur when two miners find a valid next block at the same time.

  4. It’s important to see if the block was accepted by the network.

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#4636
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Adjacent nodes to each miner who solved the block will pick up its new block and start working on the next block in the chain until subsequent blocks are solved and the longest chain is established.
  2. What is a stale block?
    A stale block is the block that gets dropped when two miners solve a block at the same time. Once a new block is added to the end of one of the different chains and is accepted, the other block that had been solved at the same time becomes null and void, or stale, and rejected from the blockchain.
  3. How do stale blocks occur?
    When two miners solve a block at the same time. Eventually one will prevail by having more subsequent blocks added on.
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    In case of stale blocks, it’s not safe to assume a transaction is confirmed right when the block is solved or even 2-3 after. Six is best to be certain the transaction has been confirmed into an accepted block.
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#4637
  1. What happens in the bitcoin network when two miners solve a block at the same time?

The blockchain temporarily forks making two versions of the blockchain.

  1. What is a stale block?

A block that started to propagate but was later rejected.

  1. How do stale blocks occur?

When two different nodes produce blocks at the same time. One block will be accepted by the rest of the miners and the other will be rejected sending the transactions in the rejected block back to the Mempool.

  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

It is important to wait for more than one block to be confirmed to avoid your transactions being in the rejected block and getting sent back to the Mempool

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#4638

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Two “versions” of the block will be stale until one of them is confirmed (best practice 6 times).

  2. What is a stale block?
    A stale block is a block which has been mined and propagation started, but it has not been confirmed yet as part of the longest blockchain.

  3. How do stale blocks occur?
    When multiple blocks are mined at the same time / height by miners.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    So that the blocks have enough time to be propagated accross the network

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#4639
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    It seems that the next block added to the chain will determine which block to continue on and then the other block becomes orphaned, and transactions are returned to the mempool
  2. What is a stale block? The block that the blockchain is not used to continue the chain and is rejected
  3. How do stale blocks occur? Two miners create two blocks at the same time, yet only one will continue the chain
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction? So that subsequent blocks are addended to the proper chain,
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#4640

What happens in the bitcoin network when two miners solve a block at the same time? One with more difficulty is validaited

What is a stale block? Transaction from miners that were not validated and go back to mempool

How do stale blocks occur? when the block is not accepted

Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction? You have stale blocks which need to go back to mempool.

#4641

Stale Blocks are blocks that were completely valid blocks in the chain at one point but then got dropped because there’s another version of the blockchain that’s longer.

#4642

Stale blocks occur when two miners solve and append a different block on the chain at the exact same time, or two blocks on two chains are competing with each other. But there should only be one version of truth, i.e. the longer chain with the most proof of work such that blocks appended on the shorter chain following the fork will have to be dropped and moved to mempool.

#4643

  1. When two miners solve a block at the same time, the one with the longest blockchain wins and the loser becomes a stale or orphaned block and all the transactions are returned to the mempool

  2. A stale block is a block that was discarded when another block that was mined at the same time has a loner blockchain,

3, A block that was valid for a while then becomes stale when another block that was mined at the same time has a longer blockchain.

  1. It is important to wait that long in case of a stale block occurring.
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#4644
  1. new blocks keep getting added and eventually the longest chain wins. In that case, the losing blocks get dropped off the chain
  2. Stale block is a valid block that gets dropped out of the chain because it is not part of the longest chain
  3. they occur when 2 miners solve the puzzle simultaneously thereby creating 2 valid blocks at the same time
  4. To ensure that your transaction is finally part of the blockchain (6 confirmations)
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#4645

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    They both get appended to the blockchain, creating a fork of 2 versions of the truth.

  2. What is a stale block?
    A stale block is an abandoned block, whose transactions are returned to the mempool, resulting from the mining network choosing the other fork presented in the case of 2 blocks getting appended at the same time.

  3. How do stale blocks occur?
    In the case of 2 blocks presented to the blockchain at exactly the same time, both would be accepted, creating the fork of 2 versions of truth. Future miners will have to choose between each of the forks to append their blocks to, and the first one chosen becomes the primary fork. The other fork is severed from the blockchain and it’s transactions returned to the mempool to be processed into the next block.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    To confirm you are choosing a block that will not be orphaned.

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#4646
  1. When two miners solve a block at the same time in the bitcoin network they are both appended to the blockchain, Whichever block ends up having the next blocks appended to it becomes the blockchain and the other block gets dropped and the transactions from that block return to the mempool.
    2.A stale block is a block that was once in the blockchain but got dropped.
    3.A stale block occurs when 2 miners append a block to the blockchain at the same time creating a competition between the two blocks to create the longer chain.
    4.It is important to wait for more than one block to be confirmed when sending or receiving a transaction in the blockchain because it is possible for your transaction to end up in a stale block.
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#4647
  1. If two miners solve the puzzle at the same time they are both added to the blockchain at a fork in the chain. The nodes will confirm the new blocks and during this time another block can be add to one of the forks and then once that path is longer the short chain will be discarded sending all transactions to the mempool.
  2. A stale block will be the block that has been omitted from the chain after it was found to be the shortest chain link.
  3. Stale blocks occur when more than one miner has solved the puzzle and their block was added to the blockchain at the same time. It will become a stale block once the nodes have determined which block will become the next link in the chain and release the other from the chain. Because only the longest chain will be verified.
  4. Due to number 3 answer this is why you should wait for at least 6 more blocks to be added so you know for sure your transaction doesn’t become a stale block and your transaction goes back into the mempool
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#4648
  • What happens in the bitcoin network when two miners solve a block at the same time?
    A: The blockchain will have two versions of the truth.
  • What is a stale block?
    A: When two miners solve a block at the same time and it result in two versions of truth, one version will eventually be rejected. Stale blocks are the blocks created in the rejected chain, whose transactions are sent back to the mempool.
  • How do stale blocks occur?
    A: They are largely caused due to the fact miners are globally distributed and the network latency which comes with that, i.e.: the speed at which new blocks are communicated to nodes around the world. The result is it can take some time for the final version of the truth to emerge.
  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    A: It can take some time for the final version of the truth to be verified. If you took the first confirmation as being a finalised transaction and that block was then orphaned, you wouldn’t actually be certain it was finalised. Waiting for multiple block before treating a transaction as final ensures that it is indeed final.
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#4649

Homework - stale blocks

What happens in the bitcoin network when two miners solve a block at the same time?
There will be 2 correct and active chains until the next miner will mine a block.

What is a stale block?
A stale block is a correct block that has not been build on when a other chain was active.

How do stale blocks occur?
The block in the blockchain where the next miner builds on will become dominant and rule out the chain that has less blocks making the one that wasn’t built one the “stale block”

Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
Because that would rule out that your transaction might have been in a stale block.

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#4651

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    They both are temporarily on the blockchain until the next node picks up one or the other. The next node will pick up the block with the most previous work done and from there whichever block is chosen will be considered the truth moving forward and the other block will fall of and become a stale block

  2. What is a stale block?
    A block that was successfully mined, but is no longer included in the blockchain as it was superseded by the block that was added to the chain first. The stale block then falls off, goes back to the mempool and miners work off the block that was added to the chain firs

  3. How do stale blocks occur?
    When two miners mine a block at the same time, but the next node chooses the block with the longest chain (most work). Then all future blocks are mined off the block that was chosen and the stale block falls off the chain

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

It’s not officially confirmed until 6 confirmations.

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#4652

What happens in the bitcoin network when two miners solve a block at the same time?
=> We have a split chain, i.e. we have two versions of the blockchain. This happens because both miners will broadcast their version of the blockchain. Nodes will choose the version of the blockchain that got to them first.
A split chain is resolved when a new block is mined. This new block will use one of the chains and , when nodes are notified of the new chain containing the new block, they will drop other versions of the blockchain with less work (i.e. “shorter”)

What is a stale block?
=> When nodes drop the shorter chain (i.e. the chain with less work), the blocks that are dropped are called stale blocks.

How do stale blocks occur?
=> When a node drop a shorter chain in favour of a longer chain (i.e. a chain with more work)

Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
=> Because blocks might be dropped (in case of a split chain for instance) , causing all block´s transactions to go back to the Mempool . Waiting for several confirmations (> 6) means it is extremely unlikely (virtually impossible) that a transaction will be part of of a block that will be dropped.

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#4653

  1. Both blocks will be accepted and broadcasted to new nodes. Miners will then choose one of these blocks to add to. Whichever is added first will be the accepted block .

  2. The block that is not accepted @ above becomes a stale block. A stale block takes the transactions that were in it and releases them back to the mempool.

  3. A stale block occurs when two blocks are simultaneously accepted, and the block that isn’t built on after is considered stale.

  4. Because you need to make sure that the transaction processes and isn’t put into a stale block.

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#4654
  1. They wait until a new block is mined. Which ever block is linked to then becomes the longest chain and will be accepted as truth.
  2. A stale block is a block that was thought to be true but was then subsequently dropped from the chain
  3. " blocks both thought to be correct are added to the chain, when one block after 10 mins has another added to it the other, a stale block is dropped is dropped .
  4. To mitigate the occurences of stale block
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#4655

  1. 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, the miner with the longer blockchain has his blocks validated and appended to the blockchain the other unconfirmed blocks are returned to the mempool.

  2. What is a stale block?
    A stale block is a block which has been dropped by the network in order to confirm a longer blockchain (POW).

  3. How do stale blocks occur?
    Stale blocks occur when they are produced at the exact time on the network, and all the nodes decide to validate a longer chain, these invalidated blocks are then returned to the mempool in order to be re-mined.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Due to this network of nodes being all over the world, its important to wait for more than one block to be confirmed when sending or receiving a transaction to give all nodes an opportunity to have all the information and be in agreement regarding the blockchain in order to minimize the issue regarding stale blocks.

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