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Questions tagged [time]

Time is a dimension in which events can be ordered from the past through the present into the future, and also the measure of durations of events and the intervals between them.

Time is a dimension in which events can be ordered from the past through the present into the future, and also the measure of durations of events and the intervals between them.

It has been said that time is used by the universe to ensure that everything doesn't happen all at once.

It has also been said that: "Time is an illusion, lunchtime doubly so." Not everyone agrees on the nature of time, and time is not fully understood even today.

Because human time perception can be wildly inaccurate, and many system services rely on the close synchronization of clocks, we have specialized clocks do the measurement of time for us. On the Internet, data from these clocks is made available via .

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What is the clock frequency inside 10Gb and 100Gb Ethernet cards?

As I understand, a 10Gb Ethernet card is capable of putting 10Gb every second on (say) a fibre optics cable. Now naively, for this to happen in hardware, one will need a 10GHz clock running the network card. It is possible to half that frequency by…
Randomblue
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Should servers have their timezone set to GMT/UTC?

This may not be a big deal for smaller shops that only have one or a few site, but for larger organizations this is something I'm curious about. What are the pros and cons have having all/most of your server in UTC? It would certainly help in…
user57244
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dmesg time vs system time time isn't correct

I hope that here is somebody that can help me with this strange problem. I think that i know why it is happening but i don't know how to solve it. Maybe it is because the BIOS time isn't set correct or something like it. But i don't want to change…
g00gle
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DHCP Options for Network Time Server

It looks like there are two options for providing network time settings to a DHCP client; option 004 and option 042. The description for 004 is "Time Server", while 042 specifies NTP. Is there a reason to use one or the other, or is it just vendor…
TimM
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How to make Jenkins CI use Local time instead of UTC on debian squeeze

I have a Jenkins-ci installation on a debian squeeze. Current default time zone: 'America/Toronto' Local time is now: Mon Jul 9 16:00:57 EDT 2012. Universal Time is now: Mon Jul 9 20:00:57 UTC 2012. In the /etc/default/rcS file i have…
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What is the largest hardware clock update the Linux kernel "11-minute mode" can make?

When certain time-related programs (like ntpd) are running on a Linux system, the kernel will switch into so-called "eleven minute mode" (see the hwclock man page) whereby it will automatically update the hardware clock from the system clock every…
QuantumMechanic
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What is the best way to measure latency via a "telnet to port" test, preferably with built-in Linux tools?

I'm writing a Graphite/Diamond collector measuring network latency. Specifically it should measure the time it takes to open up a connection to a port on a remote server. And it needs to work via script, i.e. no humans on the keyboard running this…
r3cgm
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Linux kernel detecting wrong processor frequency

After a cold boot of a 6.0.8 Debian server (HP ProLiant), ntpd played havoc with system time: offset and jitter with respect to the usual and reliable reference time servers growing without limit. (Note that a twin identical server had no problem at…
Stefano M
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What is the strategy for detecting time drift in a linux based data centre?

What is the strategy for detecting time drift in all linux based data centre? This is a more difficult problem than it seems at first. Time drift can cause serious problems for certain applications and often, even though NTP is installed, it's…
Stuart Woodward
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Synchronize clock with NTP while online, and with RTC while offline?

Is there a existing mechanism that synchronizes a linux system with NTP while online, and with a predictably drifting RTC while offline? We operate remote "collectors": embedded Linux systems that collect and timestamp sensor data. We need their…
Nils Toedtmann
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date: cannot set date: Operation not permitted

I have received an interesting problem during I tried to set my Server time either with NTD or manually using date command. First of all I have tried to use NTD. I have succesfully installed the latest version of NTD, started it. After that I have…
Quentin McLoad
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What is a ToD server, "Time of Day" (Not NTP)

I got a simple task: Setup a ToD server... It is not NTP. It runs on port 37. It seems to be bundled with inetd or xinetd. Shall be installed on Debian or CentOS. Alternatively FreeBSD (pfsense router). Any hint on how to proceed? Two starter links…
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Correcting CentOS System Clock

Using the time C function (number of seconds since the Epoch) shows that the time on my current CentOS 6 server is about 7 hours behind compared to another server with the correct time. How can I correct the system clock? I don't think it's drift…
user3180
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Easy way to get the International Atomic Time on linux?

My system uses UTC for the system clock, which I don't particularly feel like changing. Is there an easy way to get the current TAI time? (preferably a command line tool or flag)
JanKanis
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Time drift

How do you deal with server time drift?
deadprogrammer
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