Lines Matching +full:clock +full:- +full:out +full:- +full:frequency
1 /* -*- Mode: Text -*- */
7 prog-name = "ntpd";
8 prog-title = "set clock via Network Time Protocol daemon";
11 #include ntpdbase-opts.def
14 explain = <<- _END_EXPLAIN
17 doc-section = {
18 ds-type = 'DESCRIPTION';
19 ds-format = 'mdoc';
20 ds-text = <<- _END_PROG_MDOC_DESCRIP
27 Network Time Protocol (NTP) version 4, as defined by RFC-5905,
29 version 3, as defined by RFC-1305, and versions 1
30 and 2, as defined by RFC-1059 and RFC-1119, respectively.
34 utility does most computations in 64-bit floating point
35 arithmetic and does relatively clumsy 64-bit fixed point operations
92 doc-section = {
93 ds-type = 'USAGE';
94 ds-format = 'mdoc';
95 ds-text = <<- _END_MDOC_USAGE
105 groom the data and set the clock.
110 interval of 64s, several minutes can elapse before the clock is
112 This initial delay to set the clock
122 time-of-year (TOY) chip to maintain the time during periods when
135 reliable action is for the operator to intervene and set the clock
146 clock will be set to the server time regardless of the chip time
150 CMOS battery fails or the clock counter becomes defective, once the
151 clock has been set an error greater than 1000s will cause
157 adjusts the clock in
162 the synchronization distance, which is equal to one-half the
170 offset, steps the clock to the indicated time.
172 reduces the false alarm rate where the clock is stepped in error to
175 As the result of this behavior, once the clock has been set it
183 which would cause the clock to be set backwards
184 if the local clock time is more than 128 s
190 option is included on the command line, the clock will
198 to 500 parts-per-million (PPM) as a consequence of the correctness
201 As a result, the local clock can take a long time to
203 clock is outside the acceptable range.
205 local clock will not be consistent with any other network clock and
210 frequency errors are present the resulting time offsets stray
211 outside the 128-ms range and an eventual step or slew time
214 frequency error is so large that the first sample is outside the
221 is to quickly correct the frequency and restore operation to the
227 step/slew corrections and subsequent frequency corrections.
241 to get the system clock close to correct before starting
251 if you really need to set the clock before starting
268 will effectively "warm-start" and your system's clock will
282 as much time as possible to get the system's clock synchronized and stable.
289 monotonically-increasing time,
291 .Xr ntp-wait 1ntp-waitmdoc
297 .Xr ntp-wait 1ntp-waitmdoc
301 .Ss "Frequency Discipline"
305 frequency file, usually
309 contains the latest estimate of clock frequency error.
315 the particular system clock oscillator time and frequency error.
317 frequency are set to nominal values and the
320 normal mode, where the time and frequency are continuously tracked
322 After one hour the frequency file is
323 created and the current frequency offset written to it.
328 frequency is initialized from the file and enters normal mode
330 After that the current frequency offset is written to
344 monitoring for small changes in frequency and trimming the clock
346 However, it can operate in a one-time
347 mode where the time is set from an external server and frequency is
348 set from a previously recorded frequency file.
351 compute server-client propagation delay correction factors and
363 incidental roundtrip delay jitter and oscillator frequency wander
394 setting the clock for the first time.
396 setting the clock is the same as in continuous mode; most
404 the clock is set in about 10 s.
406 couple of minutes, the daemon times out and exits.
413 When kernel support is available to discipline the clock
414 frequency, which is the case for stock Solaris, Tru64, Linux and
416 a useful feature is available to discipline the clock
417 frequency.
421 selected servers in order to measure and record the intrinsic clock
422 frequency offset in the frequency file.
424 the frequency and offset to settle down.
428 stopped and run in one-time mode as required.
430 frequency is read from the file and initializes the kernel
431 frequency.
460 conditions, once the clock discipline loop has stabilized the
463 However, this assumes the intrinsic clock frequency error
477 updated once per hour and is available to initialize the frequency
479 .Ss "The huff-n'-puff Filter"
490 The huff-n'-puff filter is designed to correct the apparent time
516 doc-section = {
517 ds-type = 'FILES';
518 ds-format = 'mdoc';
519 ds-text = <<- _END_MDOC_FILES
520 .Bl -tag -width /etc/ntp.drift -compact
531 doc-section = {
532 ds-type = 'SEE ALSO';
533 ds-format = 'mdoc';
534 ds-text = <<- _END_MDOC_SEE_ALSO
592 doc-section = {
593 ds-type = 'BUGS';
594 ds-format = 'mdoc';
595 ds-text = <<- _END_MDOC_BUGS
600 larger than might be desirable for an elevated-priority
609 doc-section = {
610 ds-type = 'NOTES';
611 ds-format = 'mdoc';
612 ds-text = <<- _END_MDOC_NOTES