Comment by mkl
3 years ago
I wonder if it might be closer to 40,032 hours. The official Dell wording [1] is "after approximately 40,000 hours of usage". 2^57 nanoseconds is 40031.996687737745 hours. Not sure what's special about 57, but a power of 2 limit for a counter makes sense. That time might include some manufacturer testing too.
[1] https://www.reddit.com/r/sysadmin/comments/f5k95v/dell_emc_u...
It might not be nanoseconds, but something that's a power of 2 number of nanoseconds going into an appropriately small container seems likely. For example, a 62.5MHz counter going into 53 bits breaks at the same limit. Why 53 bits? That's where things start to get weird with IEEE doubles - adding 1 no longer fits into the mantissa and the number doesn't change. So maybe someone was doing a bit of fp math to figure out the time or schedule a next event? Anyway, very likely some kind of clock math that wrapped or saturated and broke a fundamental assumption.
53 is indeed a magic value for IEEE doubles, but why would anybody count an inherently integer value with floating-point? That's a serious rookie mistake.
Of course there's no law that says SSD firmware writers can't be rookies.
Full stack JS, everything is a double down to the SSD firmware!
See! People should register via mail for those important notifications! (Or alternatively do quarterly checks that your firmware is up to date).
A lot of companies have teams dedicated to hardware that don’t give a shit about it. And their managers don’t give a shit.
Then the people under them who do give a shit, because they depend on those servers, aren’t allowed to register with HP etc for updates, or to apply firmware updates, because “separation of duties”.
Basically, IT is cancer from the head down.