3 ms·

Apparently it's important for tracking the order of operations. I don't know why a ledger couldn't be kept. https://arstechnica.com/apple/2016/06/digging-into-

• phaemon 10y ago
  Hah, you were too quick for me! Must type faster!
• moomin 10y ago
  If it's anything like systems I'm familiar with, it is a ledger: if two things happen at exactly the same time, one happens a nanosecond later.
• simonh 10y ago
  A ledger is a separate write that slows down I/O and uses up disk space. Any way the question should by why a ledger wasn't used, not why it couldn't. Of course it could, but it's not necessarily desirable.