31–40 of 128 posts
Why not just synchronize to GPS time? It is pretty straightforward to get hardware timestamp on the 1PPS from the GPS. And then your time is as precise as the GPS clock, which can have a rubidium standard.
I was actually reading about this recently and learned about the time problem. Some interesting stuff I remember: * On LAN: NTP can get up to 1ms accuracy and on WAN about 10ms accuracy. * People's 'system clocks' use NTP for synchronization but can still be completely off. * When you call DataTime.now() in Javascript it returns the unix timestamp in UTC time. * Since it is UTC it will have the same value anywhere in…
One bit of clarification: > it returns the unix timestamp in UTC time Unix timestamp is ALWAYS the number of seconds since January 1st, 1970 00:00:00 UTC. It cannot be in any timezone.
Sorry for the ignorance, but what is the point of getting this accurate in the datacenter (outside of scientific research and measurements I'd imagine)? Wouldn't it be easier to just make distributed servers deal with large 'packets' or large individual tasks on their own?
Earlier quoted context omitted.
None of the services you mentioned need even close to nanosecond precision between servers to operate. Applications that do (other than the ones in the article like Spanner) are concentrated in supercomputing/scientific computing and spend a LOT of money on the problem. So yeah if you are letting your clocks drift by multiple seconds you aren't "using time" in any real sense. If these folks can achieve what they want…
Telco workloads and 5g require precise time using technologies like ptp. The cheaper, more commodity those solutions get the better.
If one has such an accurate clock they might be able to accurately plot their position on earth to within 1 ft merely by checking the timed pulses of orbiting satellites.
> “Currently, nobody uses time except for maybe Spanner at Google, CockroachDB or someone doing database things,” Rosenblum said. “We believe that there’s a lot more places, especially as more and more time-critical things came up. We can do time sync, since we figured out how to do that pretty well. And so we asked: is this part of a trend where we’re going to start programming these systems differently? And [resear…
Reminds me of early in my career where I encountered a home made time sync system because the creator had never heard of NTP.
IEEE 1588 (Precision Time Protocol) has already solved this problem for every use case that matters and offers microsecond precision. https://www.eecis.udel.edu/~mills/ptp.html PTP takes advantage of special Ethernet switches and other devices which can decode or manipulate the time tags in hardware because yes your switches add latency. This just sounds like more horseshit out of SV. I applaud them for convincing so…
Earlier quoted context omitted.
None of the services you mentioned need even close to nanosecond precision between servers to operate. Applications that do (other than the ones in the article like Spanner) are concentrated in supercomputing/scientific computing and spend a LOT of money on the problem. So yeah if you are letting your clocks drift by multiple seconds you aren't "using time" in any real sense. If these folks can achieve what they want…
Makes me curious how accurate a GPS clock is, they must be pretty good given the timing precision needed for accurate positioning.
> “Currently, nobody uses time except for maybe Spanner at Google, CockroachDB or someone doing database things,” Rosenblum said. “We believe that there’s a lot more places, especially as more and more time-critical things came up. We can do time sync, since we figured out how to do that pretty well. And so we asked: is this part of a trend where we’re going to start programming these systems differently? And [resear…
None of the services you mentioned need even close to nanosecond precision between servers to operate. Applications that do (other than the ones in the article like Spanner) are concentrated in supercomputing/scientific computing and spend a LOT of money on the problem. So yeah if you are letting your clocks drift by multiple seconds you aren't "using time" in any real sense. If these folks can achieve what they want…
I considered starting a competitor in 2018 when I first saw this company, but I don't have the same connections to customers that these guys do.
My conclusion was that PTP precision with software timestamps would be a good company, but not something between. I hope they can prove me wrong!