This is a simple question: could a miner seal multiple sectors simultaneously. If possible, how?
Currently when I go through the code, it looks a miner only could handle one sector for sealing. It is no problem usually when a miner is not that powerful and sealing is really resource consuming. It is fully understood that a sealing process should take a great deal of time and it should not be unlimited speed up even there are more resources available. The algorithm should guarantee the period of sealing is long enough with defined dependences.
But, if the miner capacity allows, we should be able to do multiple sealing simultaneously, in this way, the resources could be fully utilized, and, since each sealing process still takes long enough, the security of the proving should not be weakened.