How is the Ethereum Classic gas limit enforced?

Question

According the the Ethereum Classic Technical Reference:

For security reasons, the amount of gas that can be purchased and used by blocks is limited.

How is it limited? Do miners choose to limit it, or is there a limit in the protocol itself?

More broadly, is there an explicit or implicit block-size limit with Ethereum Classic? My understanding is that on Ethereum the gas limit is a concensus limit, that miners can increase it, and at some points they have done so. Is Ethereum classic also like this? Or does it have a hard limit in code?

Answer 1

Ethereum Classic block gas limit works the same as Ethereum. When a miner creates a block, they can choose any gas limit for it that is between parentGasLimit - floor(parentGasLimit/1024) and parentGasLimit + floor(parentGasLimit/1024). Anything outside those bounds make the block invalid.