[DCP-o-matic] When are hashes created

Hi Carl. I have a rather obscure question: At what point in the process of DCP encoding are the hashes calculated? Reason I am asking is that I have been making a large batch of DCPs but now I suspect that one of the drives I've been using is faulty. Some other files on the drive have become corrupt. I've checked that all the DCPs on that drive pass a hash-check, but... are the hashes calculated: 1. As the MXF files are created *before* they are written to disc? or 2. Files written to disc first, and then read back from disc afterwards to calculate hashes? Because DCP-o-matic has the lengthy "calculating checksums" phase at the end of encode, I am suspecting it might be the latter. If it is, then I am wondering if it's possible some of the DCPs I've made are corrupt. I'm thinking that if any of the data got corrupted between DCP-o-matic writing it to disc and then reading it back again to calculate the hashes, the hashes would reflect the corrupted data. And so the fact that my hash-check passes wouldn't guarantee the DCP is as it should be. Or is there some other integrity checking process which would make this impossible? Sorry for rather random question. Many thanks, Jim