Not sure if you are being disingenuous or you really don't understand. I'll give you the benefit of the doubt and assume the latter.
BIP101 activates *only* if XT has >75% of hashing power.
No, it activates when >75% of the last 1000 blocks *say* they were mined by XT. That can happen with less than 75% of the hash power saying they are running XT, and you also can't assume that just a block was mined by XT just because it says it was. It is quite possible for me to mine blocks saying I'm willing to accept "big blocks" when I'm actually not.
So once a big block is mined then it doesn't matter if core ignores it, because core doesn't have the hash power to be able to orphan XT blocks by producing a longer chain.
From Bitcoin's point of view, XT's "big blocks" don't exist, so the question of whether or not it can orphan them is moot. Core will continue to work on the longest valid chain, and that doesn't include any chain with blocks greater than 1MB in it.
At the point a big block is mined the probability of core being able to produce a longer chain quickly falls to zero.
The longest valid chain accepted by Core *is* the longest valid chain, by definition. If 75% of the hash power wants to mine an incompatible fork of Bitcoin, that doesn't change this fact. But mining is expensive. Miners won't mine Mike's coin once they find they can't cover their expenses by selling them.
In the first 10 minutes there is a 25% chance, in 20 minutes 6% chance and so on... 1.5%, 0.4%,0.1%. After on hour of XT mining with 75% hashpower there is a 0.02% chance that core has a longer chain. Core is dead in an hour.
Litecoin forked from Bitcoin. Its chain grows 4 times faster than Bitcoin's. There's a 0% chance that Bitcoin can catch up with the length of Litecoin's chain. Nobody cares. Core ignores the Litecoin chain in the same way that it will ignore the XTcoin chain once XT's chain becomes incompatible with Bitcoin's.
If XT doesn't have 75% of hashing power then BIP101 doesn't activate. So both XT and core both continue to mine small blocks and nothing changes.
You seem to be repeating yourself. See my first paragraph.
The chart is quite correct.
Not really. "the longest chain" is ambiguous. It should really be "the longest valid chain", and then you need to define which coin's concept of "validity" you're using. Every client follows the longest valid chain - that's precisely how they decide which chain to follow.
So assuming the question is "will my node follow the longest valid Bitcoin chain?", then the answer is "no" for XT once BIP101 is activated. At that point XT stops following the longest valid Bitcoin chain and starts following the longest valid XT chain, whereas the answer is "yes" for Bitcoin.
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If, at that moment, more than 50% of the miners accept big blocks, the big-block branch (mined by them) will eventually grow faster than the small-block branch (mined by the rest of the miners). The split will be permanent and the big-block branch will grow faster.
Why would the split be permanent? Miners are free to switch between chains at any point, and will mine whichever chain gives them the best payouts. If XTcoin is valued significantly below Bitcoin then miners will switch back to mining Bitcoin and the Bitcoin chain will catch and outgrow the XT chain.
If, at that moment, less than 50% of the miners accept big blocks, the small-block branch will eventually grow longer. Then the big-block miners will stop mining their branch, which will be orphaned, and they will start mining the small-block branch too. If someone mines another big block, the chain will split again. This situation will repeat over and over, as long as some miner happens to mine a big block. There will be a single small-block chain with recurrent big-block side branches that are orphaned sooner or later.
Only from XT's point of view. From a Bitcoin user's point of view those orphaned blocks never existed.
Sane bitcoiners should want the first case to happen
Have you read BIP101? It proposes jumping the blocksize limit to 8 MB next year, and then doubling of the blocksize limit every 2 years, for 20 years. That gives us 8192 MB blocks in 21 years. And that's what the sane bitcoiners should want?
Blockstream fans who are not totally stupid [...]
Bitcoiners who are stupid, or are into financial sado-masochism [...]
So there are only 3 categories:
* the 'sane' ones who want an 8 GB blocksize limit
* blockstream fans
* stupid and/or BDSM types
How about those who would prefer a more sensible raising of the blocksize limit once consensus has been reached, rather than this ham-fisted 8 GB blocksize limit nonsense?
