multiple transactions in a block

[CliffordM]

Am I right in thinking that a bitcoin can only be used ONCE per block ?

My reasoning works along the lines that there is no way of imposing an ordering of transactions in a block -- which could potentially invalidate a multiple use in block.


IF this is true, then it creates a limit of total volume tradeable per day , given on average there is a block every 10 minutes.

This then creates a relationship between total volume transacted and the value of a bitcoin ?

[1713927118]

1713927118

[kokjo]

1. there is no such thing as ONE BITCOIN.
2. the ordering of the transactions in a block is important, at least for merkel-trees
3. a transaction can be spend within the confirming block.

Example of 3.:
mtgox greenaddress(http://blockchain.info/address/1LNWw6yCxkUmkhArb2Nf2MPw6vG7u5WG7q?sort=1)
transaction A(http://blockchain.info/tx/2991662884eb4183898aac1bc44159346fb8a9a41fb3693db5214e92abd456eb)
transaction B(http://blockchain.info/tx/bb2db3dd98c04bd0cb9e9d6f392b2b19537219c05b8a149cac7db12e7457be4b)
block 183646(http://blockchain.info/block-index/183646/00000000000009af7a43f531cf64962016539640ee7f24c3f4b452e60e643759)

[DannyHamilton]

"Bitcoins" don't actually exist.  "Bitcoin" is an abstraction that is commonly used to simplify discussions about transactions.

In actuality what you have is a ledger.  Each transaction consists of one or more "Inputs" which are generally just signed references to previous transactions, and one or more "Outputs" which are generally scripts indicating what is required to use a reference to the "Output" as an "Input" in a future transaction.

It most certainly is possible for the output of one transaction to be used as an input in another transaction in the same block.  That processes could be repeated over and over, so you could have a chain of many transactions each referring the previous output all in the same block.

[Stephen Gornick]

Am I right in thinking that a bitcoin can only be used ONCE per block ?

Nope.

Both the parent and child transactions can be included in the same block.  I'm using the term "child" to refer to one which uses an output of a "parent" transaction which also has not yet been included in any prior block.

If I remember correctly, the bitcoin.org client will arrange transactions in the block so that parent's transaction occurs first and child transaction(s) occur later in the block.   I am unsure if a block that has the order reversed would have any problem getting accepted by other nodes if that isn't the case.

[Bitobsessed]

If you had 2,100,000,000,000,000 people(or I guess just separate wallets) with only 0.00000001 BTC and they all spent it at the same time, it might be a problem...lol

Someone correct me here if I am wrong but I think each block has a size limit of 1MB and blocks now are 47.93kb - 272.76kb on blockchain.info