以太坊硬分叉后一个币是不是变成了 2 个币

如果有算力支持,大家愿意忍受分叉前的网络所有的问题,那确实可以变成两条链。这就是当年为什么有ETC和ETH,但显然ETC现在面临很多开发的问题,因为用的相对较老的构架,很多已经被ETH解决的问题ETC还无法解决。

本次硬分叉是使用 EIP150 中提到的是按 (1) 还是 (2) 来实行?

根据EIP150中的1-c进行
Specification (version 1)

If block.number >= FORK_BLKNUM, then:

Increase the gas cost of EXTCODESIZE to 700
Increase the base gas cost of EXTCODECOPY to 700
Increase the gas cost of BALANCE to 400
Increase the gas cost of SLOAD to 200
Increase the gas cost of CALL, DELEGATECALL, CALLCODE to 700
Increase the gas cost of SUICIDE to 5000
Increase the recommended gas limit target to 5.5 million
If a call asks for more gas than the maximum allowed amount, do not return an OOG error; instead, call with the maximum allowed amount of gas (this is equivalent to a version of #90)
That is, substitute:

        extra_gas = (not ext.account_exists(to)) * opcodes.GCALLNEWACCOUNT + \
            (value > 0) * opcodes.GCALLVALUETRANSFER
        submsg_gas = gas + opcodes.GSTIPEND * (value > 0)
        if compustate.gas < gas + extra_gas:
            return vm_exception('OUT OF GAS', needed=gas+extra_gas)

With:

        extra_gas = (not ext.account_exists(to)) * opcodes.GCALLNEWACCOUNT + \
            (value > 0) * opcodes.GCALLVALUETRANSFER
        if compustate.gas < extra_gas:
            return vm_exception('OUT OF GAS', needed=extra_gas)
        if compustate.gas < gas + extra_gas:
            gas = compustate.gas - extra_gas
        submsg_gas = gas + opcodes.GSTIPEND * (value > 0)

Specification (version 1c)

All of the above, and:

If SUICIDE hits a newly created account, it triggers an additional gas cost of 25000 (similar to CALLs)