NTPsec

c-ntpsec-7-day-stats

Report generated: Mon Oct 19 15:03:32 2020 UTC
Start Time: Mon Oct 12 15:03:28 2020 UTC
End Time: Mon Oct 19 15:03:28 2020 UTC
Report published: Mon Oct 19 08:03:50 2020 PDT
Report Period: 7.0 days

Local Clock Time/Frequency Offsets

local offset plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Time Offset -2.036 -0.983 -0.723 -0.010 0.744 1.085 2.178 1.467 2.068 0.455 -0.005 µs -3.927 9.631
Local Clock Frequency Offset -5.418 -5.403 -5.367 -5.179 -5.083 -5.069 -5.066 0.283 0.334 0.087 -5.196 ppm -2.231e+05 1.354e+07

The time and frequency offsets between the ntpd calculated time and the local system clock. Showing frequency offset (red, in parts per million, scale on right) and the time offset (blue, in μs, scale on left). Quick changes in time offset will lead to larger frequency offsets.

These are fields 3 (time) and 4 (frequency) from the loopstats log file.



Local RMS Time Jitter

local jitter plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Time Jitter 80.000 112.000 131.000 193.000 297.000 383.000 905.000 166.000 271.000 54.739 201.038 ns 28.75 121.3

The RMS Jitter of the local clock offset. In other words, how fast the local clock offset is changing.

Lower is better. An ideal system would be a horizontal line at 0μs.

RMS jitter is field 5 in the loopstats log file.



Local RMS Frequency Jitter

local stability plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Frequency Jitter 25.000 36.000 45.000 98.000 231.000 331.000 549.000 186.000 295.000 60.790 112.296 10e-12 4.827 17.67

The RMS Frequency Jitter (aka wander) of the local clock's frequency. In other words, how fast the local clock changes frequency.

Lower is better. An ideal clock would be a horizontal line at 0ppm.

RMS Frequency Jitter is field 6 in the loopstats log file.



Local Clock Time Offset Histogram

local offset histogram plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Offset -2.036 -0.983 -0.723 -0.010 0.744 1.085 2.178 1.467 2.068 0.455 -0.005 µs -3.927 9.631

The clock offsets of the local clock as a histogram.

The Local Clock Offset is field 3 from the loopstats log file.



Local Temperatures

local temps plot

Local temperatures. These will be site-specific depending upon what temperature sensors you collect data from. Temperature changes affect the local clock crystal frequency and stability. The math of how temperature changes frequency is complex, and also depends on crystal aging. So there is no easy way to correct for it in software. This is the single most important component of frequency drift.

The Local Temperatures are from field 3 from the tempstats log file.



Local Frequency/Temp

local freq temps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -5.418 -5.403 -5.367 -5.179 -5.083 -5.069 -5.066 0.283 0.334 0.087 -5.196 ppm -2.231e+05 1.354e+07
Temp ZONE0 56.382 56.920 57.458 59.610 61.224 62.300 62.838 3.766 5.380 1.333 59.526 °C

The frequency offsets and temperatures. Showing frequency offset (red, in parts per million, scale on right) and the temperatures.

These are field 4 (frequency) from the loopstats log file, and field 3 from the tempstats log file.



Local GPS

local gps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
nSats 5.000 7.000 7.000 10.000 12.000 12.000 13.000 5.000 5.000 1.294 9.708 nSat 294.2 2039
TDOP 0.470 0.540 0.600 0.810 1.400 1.610 5.390 0.800 1.070 0.245 0.865 25.56 113.7

Local GPS. The Time Dilution of Precision (TDOP) is plotted in blue. The number of visible satellites (nSat) is plotted in red.

TDOP is field 3, and nSats is field 4, from the gpsd log file. The gpsd log file is created by the ntploggps program.

TDOP is a dimensionless error factor. Smaller numbers are better. TDOP ranges from 1 (ideal), 2 to 5 (good), to greater than 20 (poor). Some GNSS receivers report TDOP less than one which is theoretically impossible.



Server Offsets

peer offsets plot

The offset of all refclocks and servers. This can be useful to see if offset changes are happening in a single clock or all clocks together.

Clock Offset is field 5 in the peerstats log file.



Server Offset 104.131.155.175

peer offset 104.131.155.175 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 104.131.155.175 -20.065 1.249 1.539 2.396 3.680 4.584 11.267 2.140 3.336 1.312 2.481 ms -5.73 148.2

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 162.159.200.1

peer offset 162.159.200.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 162.159.200.1 -0.799 1.268 1.583 2.033 2.780 6.207 7.618 1.197 4.939 0.692 2.146 ms 19.97 112.2

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 173.11.101.155

peer offset 173.11.101.155 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 173.11.101.155 -4.193 -1.966 -0.624 0.269 1.094 1.694 3.674 1.717 3.660 0.606 0.250 ms -2.743 13.31

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 178.62.68.79

peer offset 178.62.68.79 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 178.62.68.79 0.407 0.827 1.513 2.351 3.639 5.396 5.712 2.126 4.569 0.699 2.449 ms 24.71 100.1

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 192.168.1.10

peer offset 192.168.1.10 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 192.168.1.10 -197.294 -86.651 -44.544 22.588 84.541 109.100 233.011 129.085 195.751 38.849 20.676 µs -1.766 6.079

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 204.123.2.5

peer offset 204.123.2.5 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.123.2.5 -0.200 1.781 2.003 2.396 2.915 3.223 3.784 0.912 1.442 0.300 2.418 ms 372.5 2777

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset SHM(0)

peer offset SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset SHM(0) -72.883 -67.970 -64.525 -55.408 -46.904 -44.410 -39.682 17.621 23.560 5.347 -55.550 ms -1511 1.761e+04

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset SHM(1)

peer offset SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset SHM(1) -2.037 -0.984 -0.724 -0.011 0.745 1.086 2.179 1.469 2.070 0.456 -0.005 µs -3.928 9.625

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Jitters

peer jitters plot

The RMS Jitter of all refclocks and servers. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 104.131.155.175

peer jitter 104.131.155.175 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 104.131.155.175 0.000 0.000 0.000 1.659 9.353 13.205 19.092 9.353 13.205 3.070 2.831 ms 1.534 5.658

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 162.159.200.1

peer jitter 162.159.200.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 162.159.200.1 0.173 0.266 0.387 1.826 9.400 16.243 31.016 9.013 15.977 3.562 3.103 ms 2.484 14.47

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 173.11.101.155

peer jitter 173.11.101.155 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 173.11.101.155 0.210 0.437 0.645 2.459 11.821 21.739 42.458 11.176 21.302 4.540 4.139 ms 2.906 17.79

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 178.62.68.79

peer jitter 178.62.68.79 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 178.62.68.79 0.241 0.372 0.500 2.160 9.775 14.066 26.564 9.275 13.695 3.528 3.626 ms 1.589 6.323

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 192.168.1.10

peer jitter 192.168.1.10 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 192.168.1.10 0.008 0.030 0.050 0.154 8.683 9.069 21.392 8.633 9.039 2.628 1.207 ms 0.7098 4.71

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 204.123.2.5

peer jitter 204.123.2.5 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.123.2.5 0.177 0.245 0.351 1.748 9.178 14.110 29.713 8.828 13.865 3.413 3.112 ms 1.809 8.727

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter SHM(0)

peer jitter SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(0) 0.040 0.208 0.336 0.957 3.291 5.913 11.556 2.955 5.704 1.059 1.259 ms 3.267 14.59

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter SHM(1)

peer jitter SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(1) 33.000 78.000 107.000 235.000 555.000 798.000 1,979.000 448.000 720.000 151.576 271.766 ns 4.9 21.43

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -5.418 -5.403 -5.367 -5.179 -5.083 -5.069 -5.066 0.283 0.334 0.087 -5.196 ppm -2.231e+05 1.354e+07
Local Clock Time Offset -2.036 -0.983 -0.723 -0.010 0.744 1.085 2.178 1.467 2.068 0.455 -0.005 µs -3.927 9.631
Local RMS Frequency Jitter 25.000 36.000 45.000 98.000 231.000 331.000 549.000 186.000 295.000 60.790 112.296 10e-12 4.827 17.67
Local RMS Time Jitter 80.000 112.000 131.000 193.000 297.000 383.000 905.000 166.000 271.000 54.739 201.038 ns 28.75 121.3
Server Jitter 104.131.155.175 0.000 0.000 0.000 1.659 9.353 13.205 19.092 9.353 13.205 3.070 2.831 ms 1.534 5.658
Server Jitter 162.159.200.1 0.173 0.266 0.387 1.826 9.400 16.243 31.016 9.013 15.977 3.562 3.103 ms 2.484 14.47
Server Jitter 173.11.101.155 0.210 0.437 0.645 2.459 11.821 21.739 42.458 11.176 21.302 4.540 4.139 ms 2.906 17.79
Server Jitter 178.62.68.79 0.241 0.372 0.500 2.160 9.775 14.066 26.564 9.275 13.695 3.528 3.626 ms 1.589 6.323
Server Jitter 192.168.1.10 0.008 0.030 0.050 0.154 8.683 9.069 21.392 8.633 9.039 2.628 1.207 ms 0.7098 4.71
Server Jitter 204.123.2.5 0.177 0.245 0.351 1.748 9.178 14.110 29.713 8.828 13.865 3.413 3.112 ms 1.809 8.727
Server Jitter SHM(0) 0.040 0.208 0.336 0.957 3.291 5.913 11.556 2.955 5.704 1.059 1.259 ms 3.267 14.59
Server Jitter SHM(1) 33.000 78.000 107.000 235.000 555.000 798.000 1,979.000 448.000 720.000 151.576 271.766 ns 4.9 21.43
Server Offset 104.131.155.175 -20.065 1.249 1.539 2.396 3.680 4.584 11.267 2.140 3.336 1.312 2.481 ms -5.73 148.2
Server Offset 162.159.200.1 -0.799 1.268 1.583 2.033 2.780 6.207 7.618 1.197 4.939 0.692 2.146 ms 19.97 112.2
Server Offset 173.11.101.155 -4.193 -1.966 -0.624 0.269 1.094 1.694 3.674 1.717 3.660 0.606 0.250 ms -2.743 13.31
Server Offset 178.62.68.79 0.407 0.827 1.513 2.351 3.639 5.396 5.712 2.126 4.569 0.699 2.449 ms 24.71 100.1
Server Offset 192.168.1.10 -197.294 -86.651 -44.544 22.588 84.541 109.100 233.011 129.085 195.751 38.849 20.676 µs -1.766 6.079
Server Offset 204.123.2.5 -0.200 1.781 2.003 2.396 2.915 3.223 3.784 0.912 1.442 0.300 2.418 ms 372.5 2777
Server Offset SHM(0) -72.883 -67.970 -64.525 -55.408 -46.904 -44.410 -39.682 17.621 23.560 5.347 -55.550 ms -1511 1.761e+04
Server Offset SHM(1) -2.037 -0.984 -0.724 -0.011 0.745 1.086 2.179 1.469 2.070 0.456 -0.005 µs -3.928 9.625
TDOP 0.470 0.540 0.600 0.810 1.400 1.610 5.390 0.800 1.070 0.245 0.865 25.56 113.7
Temp ZONE0 56.382 56.920 57.458 59.610 61.224 62.300 62.838 3.766 5.380 1.333 59.526 °C
nSats 5.000 7.000 7.000 10.000 12.000 12.000 13.000 5.000 5.000 1.294 9.708 nSat 294.2 2039
Summary as CSV file


Glossary:

frequency offset:
The difference between the ntpd calculated frequency and the local system clock frequency (usually in parts per million, ppm)
jitter, dispersion:
The short term change in a value. NTP measures Local Time Jitter, Refclock Jitter, and Server Jitter in seconds. Local Frequency Jitter is in ppm or ppb.
kurtosis, Kurt:
The kurtosis of a random variable X is the fourth standardized moment and is a dimension-less ratio. ntpviz uses the Pearson's moment coefficient of kurtosis. A normal distribution has a kurtosis of three. NIST describes a kurtosis over three as "heavy tailed" and one under three as "light tailed".
ms, millisecond:
One thousandth of a second = 0.001 seconds, 1e-3 seconds
mu, mean:
The arithmetic mean: the sum of all the values divided by the number of values. The formula for mu is: "mu = (∑xi) / N". Where xi denotes the data points and N is the number of data points.
ns, nanosecond:
One billionth of a second, also one thousandth of a microsecond, 0.000000001 seconds and 1e-9 seconds.
percentile:
The value below which a given percentage of values fall.
ppb, parts per billion:
Ratio between two values. These following are all the same: 1 ppb, one in one billion, 1/1,000,000,000, 0.000,000,001, 1e-9 and 0.000,000,1%
ppm, parts per million:
Ratio between two values. These following are all the same: 1 ppm, one in one million, 1/1,000,000, 0.000,001, and 0.000,1%
‰, parts per thousand:
Ratio between two values. These following are all the same: 1 ‰. one in one thousand, 1/1,000, 0.001, and 0.1%
refclock:
Reference clock, a local GPS module or other local source of time.
remote clock:
Any clock reached over the network, LAN or WAN. Also called a peer or server.
time offset:
The difference between the ntpd calculated time and the local system clock's time. Also called phase offset.
σ, sigma:
Sigma denotes the standard deviation (SD) and is centered on the arithmetic mean of the data set. The SD is simply the square root of the variance of the data set. Two sigma is simply twice the standard deviation. Three sigma is three times sigma. Smaller is better.
The formula for sigma is: "σ = √[ ∑(xi-mu)^2 / N ]". Where xi denotes the data points and N is the number of data points.
skewness, Skew:
The skewness of a random variable X is the third standardized moment and is a dimension-less ratio. ntpviz uses the Pearson's moment coefficient of skewness. Wikipedia describes it best: "The qualitative interpretation of the skew is complicated and unintuitive."
A normal distribution has a skewness of zero.
upstream clock:
Any server or reference clock used as a source of time.
µs, us, microsecond:
One millionth of a second, also one thousandth of a millisecond, 0.000,001 seconds, and 1e-6 seconds.



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