QotD - Speaker for the Diodes — LiveJournal

05:25 am - QotD

On "that mailing list", 2005-04-20:

dsr: "In point of fact, he was the head of it. Now that he's got the pope bit set, [...]"

[someone else]: "what's the chmod command for that?"

Raul: "chmod --pope=+ cardinal
 
Note that this only works when the pope bit hasn't been set on another cardinal."

dsr: "Have you tried it? Apparently you *can* set the pope bit on two different cardinals, but then they either fight it out or schism, producing an inconsistent filesystem. Either way lots of processes die..."

Doug: "Can't do it in the same execution environment though. This situation only occurs when various systems disagree about semaphore arbitration or deadlock resolution. It's not a common implementation flaw these days."

Darren: "But what if the new Pope is being served over NFS? Is there a guarantee when the chmod takes effect?"

dsr: "No, there's still no consistent locking mechanism.
 
You can solve this with a non-NFS filesystem that guarantees rigorous locking semantics, but that's not catholic."

I asked permission to quote folks off-list, but forgot to ask whether I should use LJ userids for the ones whose LJ names I can guess. (Any of y'all want your attribution tweaked -- LJ ID, full name, whatever -- just drop me a line and I'll edit the entry.)

Later there was the observation that 'kill -9' does not work on zombie popes.