Re: [ntp:questions] Setting back-up network servers to minpoll 10 automatically when sychronizied to a referrence clock.
David, Something like this was done in NTPv3 (xntpd) and it turned out to be a bad idea. The poll interval is determined by the time constant, which for PPS and other low-stratum sources is relatively small. If a backup is switched in at a poll interval much larger than this, it takes awhile for the time constant and backup poll interval to stabilize and meanwhile the Nyquist limit is exceeded. In NTPv3 this sometimes resulted in an evil twitch until things calmed down. It gets worse in the general case where sources of unequal stratum are configured. The algorithms can result in more than one stratum survivor is present and the combine algorithm uses them all. They must all run the same poll interval or evil twitches can result. All in all, to do what you suggest requires an intricate evaluation of what already is a complicated and fragile algorithm, so this might not happen soon. Dave Thanks, Dave. It's a pity it can't work easily, but (for me) it's not a show stopper, as I have four GPS/PPS sources here. 73, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] what is a good book an the NTP that expains the math behind it
What is a good book on ntp that explains the math behind the protocal. Thanks Chip See Dave Mills' book: ISBN 0849358051 http://books.slashdot.org/story/06/05/15/143251/Computer-Network-Time-Synchronization Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Something for distributing a PPS signal?
E-Mail Sent to this address will be added to the BlackLists Null@BlackList.Anitech-Systems.invalid wrote in message news:iulje3$ahd$1...@dont-email.me... [] Unless I'm off by a magnitude somewhere; Copper wire is about 0.3m/ns? 100m ~= 333+ns? The differences in e.g. PC serial port implementations between different PPS recipients may easily cause a difference of that much. You are missing the velocity factor of typical cable, which slows the signal down to 5ns/m (round figure). But it doesn't affect your basic argument that cable delays are insignificant compared to different hardware implementations, not to mention differences in OS interrupt latency and response times. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Can't Understand NTP behaviour,
The Chinese GPS is not bad and the price is only about $35 But for not much more money you can get a nearly state of the art unit that is made and supported by a US company. Synergy will selll you an M12M Timing GPS Receiver for about $60. Look at the specs on the PDF sheet.This is gross overkill for NTP but some people use GPS for other purposes http://www.synergy-gps.com/index.php?option=com_contenttask=blogcategoryid=32Itemid=116 You can get older M12+T units from eBay for about $30 but the much better performance, US based tech suport, warenty and better documentation is maybe worth the price. Chris Albertson Redondo Beach, California Chris, Thanks for that information. The $35 Chinese kit includes the antenna and USB cable, and no extra power supply is required (get power over USB), but you do need to solder two wires. The $60 unit (I could find no prices on the site you gave) appears to be made by a Singapore company, according to the e-mail address on the specification: http://www.synergy-gps.com/images/stories/pdf/m12mt_brochure.pdf The M12M Timing GPS Receiver on its own may require a TTL to RS-232 converter, serial connectors, and 3V power source, and the M12M Timing Starter Kit uses an extra power supply (wall wart?), but requires no soldering. Great that folks can choose which suits them best. Either would be fine for using with NTP. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Can't Understand NTP behaviour,
Richard B. Gilbert rgilber...@comcast.net wrote in message news:_6idns6-1fdcpzttnz2dnuvz_rsdn...@giganews.com... [] The best source of time IMHO is a GPS Timing Receiver. Note that GPS Receivers can also be designed for navigation. For timing service you should take care to get a receiver designed for the purpose! Either kind necessarily knows what time it is but a receiver designed for Navigation is concerned with latitude, longitude, and elevation and delivering this information. Delivering accurate time is its lowest priority. There is one low-cost GPS receiver board available from China, and its use with NTP is described here: http://www.satsignal.eu/ntp/Sure-GPS.htm Many others are available, of course, such as the Garmin GPS 18x LVC. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Garmin firmware update - GPS 18x 5Hz software version 3.20
I've updated the firmware on my unit from 3.20 to 3.70 and it seems the jitter has indeed improved, see: http://i.imgur.com/6NFBA.png The middle part is when the unit was upgraded. -- Miroslav Lichvar That's good news, Miroslav, even better than expected. Thanks for posting. From those results, folk with versions of the GPS 18X LVC firmware 3.20 to 3.60 would be well advised to upgrade. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Garmin firmware update - GPS 18x 5Hz software version 3.20
Hal Murray hal-use...@ip-64-139-1-69.sjc.megapath.net wrote in message news:sekdnu74hspfmgbqnz2dnuvz_jgdn...@megapath.net... In article banlktikc4ydiycbw4no2ay2o-r+dfp9...@mail.gmail.com, steven Sommars stevesommars...@gmail.com writes: You may want to watch for several days. Previous 18x LVC firmware (3.60) drifted on my system from 0.5 to 1.4 seconds over a span of 6 days. I've been running a beta version of 3.70 for several weeks with no problems. How stable is it? I don't care what the offset is as long as it's constant. It's constant, according to a graph I've seen from Steve. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntp server specs
The problem with both of those is that the Linux machines are all going to want the PPS to be conected to the DTR pin of a serial port and for that you need rs-232 levels with wides plus and minus volts. TTL level or wose is not going to work. [] Chris Albertson Redondo Beach, California In practice, many RS-232 ports on computers will work perfectly with TTL levels. It's the DCD (carrier detect) line to which the PPS is fed on my system. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntp server specs
C BlacK rb...@non.net wrote in message news:g6kdnaptj_xcfwrqnz2dnuvz_okdn...@supernews.com... For our discussion, lets say there are many machine but the distance is not going to me more that 100ft. Then some top-of-the head sums might be: 100 machines - RS-232 input resistance, guess, 4K, all 100 in parallel 40 ohms. Voltage needed, +/- 5V, so let's guess on a 50-ohm driver source. Hence the drive voltage needs to be a little above +/- 10V, say 12V (still within RS-232 levels). Strawman suggestion, based slightly on thin-wire Ethernet: find a driver which will supply (nearly) +/-12V into an open circuit, with a 50-ohm source impedance (i.e. it supplies +/-6V into a 50-ohm load). Drive that signal into a piece of 50-ohm cable, with T-pieces used to tap off the PPS signal as required. Terminate the far end of the 50-ohm cable with the resistance required to approximately halve the open-circuit voltage of the source, thus providing an approximately correct termination to reduce any reflections. Take a look at the waveform to ensure that it's reasonably clean. Doubtless others will come up with improvements on this scheme! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Garmin firmware update - GPS 18x 5Hz software version 3.20
Eugen COCA ec...@eed.usv.ro wrote in message news:daa8a19f-fed1-4ded-84cd-d87785b42...@c41g2000yqm.googlegroups.com... The new firmware for GPS 18x PC/LVC is also available: https://buy.garmin.com/shop/store/downloadsDetails.jsp?id=4055product=010-00321-51cID=170pID=223 Changes made from version 3.60 to 3.70: Improved NMEA output timing stability. Added support to enable/disable velocity threshold filtering. Modified the PGRMID sentence format for maintaining consistency with the other NMEA sentences. Oh, that /is/ good news, Eugen, many thanks. It hasn't appeared on their RSS feed as yet, and I hadn't been checking their Web site! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntp server specs
E-Mail Sent to this address will be added to the BlackLists Null@BlackList.Anitech-Systems.invalid wrote in message news:itauip$4v0$1...@dont-email.me... David J Taylor wrote: C BlacK rb...@non.net wrote in message For our discussion, lets say there are many machine but the distance is not going to me more that 100ft. Then some top-of-the head sums might be: 100 machines - RS-232 input resistance, guess, 4K, all 100 in parallel 40 ohms. A 5v PPS signal with more than 125ma drive? Not likely from a normal TTL chip. No, you would need a suitable specified line driver, of course. A couple of transistors might do the job. 100 PC RS232 serial ports tied together, fed from one PPS driver? I'd think you would have a lot of stray ground currents running around. Even if they were isolated RS422/485 receivers, 100 in parallel, fed from one PPS driver, seems like it would be problem prone. Which is why I suggested checking the waveforms. many machines and not more than 100 feet is quite vague. It could be that 10 groups of ten (were it 100 PCs) might be better. How many PCs could be connected to a thin-wire Ethernet segment? Perhaps 30 in the 185m limit? That was working at 10Mb/s. Might be a guide as to what to aim for. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntpd + GPS + PPS + Linux (Ubuntu Lucid)
I believe there is a fix for this GPS 18x LVC problem due from Garmin in the very near future - a week or two. I will post details when I hear I'll beleive it when I see it. That they have been sitting on this problem for as long as they have does not strike one with any confidence. Some has already been testing a beta David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntpd + GPS + PPS + Linux (Ubuntu Lucid)
The garmin 18x LVM apparently has a problem that it will somtimes deliver the nmea time aver 1 second after the pulse. This makes anything think that that time is associated with t he wrong second. I believe the latest gpsd has a fudge for this, but Garmin needs to get its act togetehr. I believe there is a fix for this GPS 18x LVC problem due from Garmin in the very near future - a week or two. I will post details when I hear more. Garmin has an RSS feed for new releases. http://www8.garmin.com/company/newsroom/rssfeeds/index.html?activeBranchId=newsroom http://feeds.feedburner.com/garmin/VKiE Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] UK - Notification of GPS jamming exercises
Folks, I have received the following, relevant to the UK _ STANFORD TRAINING AREA, EAST ANGLIA, SEPTEMBER AND OCTOBER 2011 Dates: Between 19 and 23 September 2011 and between 03 and 07 October 2011 inclusive. Times: 0900 -1730 BST. Location of MULTIPLE jammers: Land based within 5km of N52° 31.0' E000° 45.0'. Frequency: A 24 MHz band centred around 1575.42MHz (GPS L1). Total Power: Up to 10 Watts EIRP. It is stressed that, as in previous exercises, Safety of Life operations will at all times take precedence over exercise activities. _ Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] UK - GPS jamming will take place: 31/05/2011 - 10/06/2011
Folks, I have received the following: Dates jamming will take place: 31/05/2011 - 10/06/2011 Time periods during which jamming will take place: Periodically Mon- Fri 09:00 - 17:30 Details of Jamming. a. Location of MULTIPLE jammers: Land based within 5km of N52° 00.881' W003° 38.518' (SN873365 - Dixie's Corner). b. Frequencies: 24 MHz bands centred around 1176.45 MHz (L5), 1227.60MHz (L2) and 1575.42MHz (L1). c. Total Power: Up to 100 Watts EIRP. Whenever possible the transmissions will be at lower powers. d. Jammers: Both omni and directional jammers to minimise affected areas. e. Affected areas will be line of sight from the jammers for land based GPS receivers. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Assistance with PPS on Windows
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrnis6idl.eqd.un...@wormhole.physics.ubc.ca... [] IIRC some BSD variants were claiming to get ~150ns? I do not believe that you can service an interrupt, and read a system clock that quickly. If you have specialised hardware on the PC (as someone suggested, a card with a counter on it which is switched on when the signal comes in) perhaps. On the nearly five-year old Windows XP system here, getting the 32-bit tick count takes 4.2 ns, and getting the full time takes about 13 ns - this from user-mode. So given the advances in processors and the different design of BSD 150ns doesn't sound impossible to me. Pretty darned good, though! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Assistance with PPS on Windows
It appears all I needed to do was swap the TX and CD pins to get it to start polling and synced to PPS. Thanks! Great! Now, a behavioral question. Will PPS be selected as the peer if and only if the peer marked preferred is also synced? What if I want PPS to act as a supplement to whichever of the stratum 1+ peers NTP sees available and decides to sync to? PPS will be the only stratum 0 reference source available to this system, but if the preferred peer goes down I would expect PPS to continue to correct the jitter of whichever other peer NTP decides to sync to (that doesn't seem to be the case). My understanding is that if you have the ATOM driver present and working (server 127.127.22.1 with serialpps.sys), that is used to refine whatever server NTP marks with a * in the ntpq -p display - the system peer. The ATOM driver itself will be marked with an o character. Also, it appears that while the preferred peer continues to be synced and polled every 64 seconds, the PPS peer seems to toggle from being a PPS peer to being rejected nearly every poll (of 16 seconds). Is this because the polling rate is different between the PPS source and the other sources, or is my serial cable too jittery? The PPS source claims to have an offset of +/- 10 ms and a jitter of between 2-3 ms depending on the poll. Thanks, Ken On a FreeBSD system, the PPS offset shows 0, and the jitter is currently 0.004 (4 microseconds). On the Windows systems here, PPS offset is typically less than 0.030 (30 microseconds), and the jitter less than 0.050 (50 microseconds). If you have a Garmin GPS 18x LVC with firmware later than 3.20, it's offset of the serial data from the PPS can exceed one second, which confuses NTP about which second the PPS actually was! In such circumstances, you can stop the serial data being used with a noselect modifier: server 127.127.20.1 minpoll 4 noselect Even without the kernel-mode serialpps.sys driver, the offset should be far less than 10 milliseconds, and the jitter far less than 2-3 milliseconds. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Not that accurate, within a second for what I need when traveling for work. But I often as not find the last choice of server(s) problematical, for some odd reason. Many hotel internet seems to be tunneled somewhere else, before it gets out to the wider www, with all the hidden latency and filtering etc. I did try synching with the office server via VPN, but that didn't work either. When I can get a vpn (one of three choices) up and working that is. Many hotels prevent vpn usage too! I guess, I could dive into the laptop, and find out why it's cmos clock keeps drifting as much as it does. Cheers. DaveB. I would try first using an accurate server (home or work) directly, and see how your PC performs. That sets a best-case limit, and over hotel Wi-Fi it will be worse. I'm surprised it's as bad as more than a second out - but I'll have my portable with me this weekend and if the hotel has Wi-Fi I'll see what I get if I have the chance. 73, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Assistance with PPS on Windows
Richard B. Gilbert rgilber...@comcast.net wrote in message news:ojmdnuvxob4wkv7qnz2dnuvz_vydn...@giganews.com... [] Getting the time into the computer takes X microseconds where X depends on the hardware and software. Windows' clock ticks every 17 milliseconds or something like that. Other operating systems also take a toll! Recent version of Windows tend to run at ~1KHz, and you can set that for Windows XP as well. If you *really* care about the nanoseconds, you don't feed them to the computer! If you must, please don't step in what comes out the other end! ;-) Indeed! Windows with a serial PPS source can achieve offsets well under 250 microseconds - see: http://www.satsignal.eu/mrtg/feenix_ntp_2.html Ken is reporting offsets of nearly 5 milliseconds, so there's something else going on. I wonder what the spec of that PPS signal is, and how all the other stuff is multiplexed onto that cable? Worth a look with the 'scope, methinks. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
I've been to some hotels in po-dunk (whatever the colloquial slang is) Europe; Wi-Fi via Sat to ISP to internet, over utilized, high latency, really low bandwidth, ... I've had colleagues in the middle of the South American jungle on similar corporate setups at base camps for new oil refineries. High bandwidth things like Adobe Flash Video will hog all their bandwidth, causing a lynch mob to hunt for the offender. Nothing like trickling Megs of firmware / software updates over something that makes analog dial-up modems look good sometimes. -- E-Mail Sent to this address blackl...@anitech-systems.com will be added to the BlackLists. Very interesting. How well did NTP work in those circumstances? I had the impression that NTP was designed to handle such links rather well. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrnis0nra.4on.un...@wormhole.physics.ubc.ca... [] Unfortunately , AFAIK, usb is terrible for delivering a PPS-- ie no interrupt lines-- the problem with having only two data lines (one beign signal ground) USB is not as good as a direct connection, but it is not terrible - see my tests here: http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html#usb PPS delivered over a serial-USB convertor which carries the DCD line shows significantly better performance than syncing over a LAN connection to a stratum-1 server. Jitter was around 45 microseconds with the PPS over USB, and about 160 microseconds when LAN synced. It could be that the faster polling with the PPS source also helped reduce the jitter. PPS over USB is likely to be significantly better than a WAN sync as well. Although I have a GPS on a USB stick, it's a logging device and I don't think that it supplies a NMEA feed. Perhaps I could test this later this year. http://www.ventusdesign.com/products/g730-ventus-gps-logger/ Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Assistance with PPS on Windows
[] The problem is we cannot get NTP to sync to the PPS output. The PPS source shows up in “ntpq –p” however it has 0 reach. System B is synced to System A and is a stable Stratum 2 server at the moment. MbgMon on System B shows the PPS output on the card is active. The IRIG signal is 100% and shows it is synced. I’ve installed the serialpps driver, rebooted and verified it was loaded in the Device Manager, set the PPSAPI_DLLS global environment variable appropriately, etc. Any suggestions on how to troubleshoot this? Thanks, Ken Ken, Dave Hart is the expert in the PPS on Windows. Could I suggest that you at least check that the pulses are being seen by checking with my Serial Port LEDs program? http://www.satsignal.eu/software/net.htm#SerialPortLEDs With NTP not running (as only one device can access the COM port), see whether there are brief white flashes on the DCD line. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrnis2psa.6vn.un...@wormhole.physics.ubc.ca... [] Jitter and accuracy are not the same thing. It would be interesting to attach the PPS to a real interrupt (ie one which can be serviced on the 1usec level) and see what the offset of the usb pps actually is. From what I read, the usb interrupts have a minimum latency of 125us but more likely much larger ( but less than 100ms). Bill, I would not be able to see offsets on 125 microseconds on the arrangement I have, only hundreds of microseconds. I don't have the time for the tests you propose, either, sorry. But from the graphs, it's obvious that the offset is well under 500 microseconds in the test configuration, at least. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
As the OP who started this (long and sometimes ammusing) thread... I do carry a GPS receiver with me, but sadly not PPS capable, I use it for location determination/tracking/navigating etc. Maybe I should include a GPS18 or 16 in the already bulging Laptop bag I lug arround. Even better if there were on on a USB stick, and you had a handy USB extension lead! In any case, with most hotel's now, you can't open the windows (the ones in the outside wall of the room, not the OS!) enough, to get anything sensible outside to get a decent view of the sky. Many do not open at all, many are also now using K Glass that has a coating on it for thermal reasons, that appears to seriously attenuate GPS signals. Yes, sometimes you're unlucky, but other times my GPS 60CSx does get a lock. I have also encountered problems many times with GPS RX's used for normal satnav purposes in the vicinity of some hotels, due I suspect to the *Huge* ammount of EM crap that seems to radiate from such establishments these days, in many, you cant even listen to FM radio in your room, let alone AM (or Shortwave for WWV etc!) So much for EMC regs eh? Not to mention power-line data transmission Even mobile phone signals are heavily attenuated (or spoiled?) in room, leaving only the expensive hotel wifi network (if it's working) as a comm's route out... Not that mobile internet is any good for timekeeping! I think from the latencies I sometime see, they use moonbounce to get back to base Free Wi-Fi is certainly one of my considerations now when choosing a hotel, and I've usually found that NTP works well enough over that. I have in one instance, had to use one of the long range BlueTooth adapters, to bt to a phone in the car, from a room (that luckily) overlooked the car park, to get any 'net conectivity. Naff latency, but I got my work done! I've also done the same trick, hoisting the phone some 50' up a mast in a plastic bag on a halyard (it was raining!) to get a signal on a remote customer site with no landline, then bt in remote sim mode to use the phone from the car! And that was just for a voice call! Never been that desperate! As earlier, the problem was a clash of interests between XP's own W32Time, and the National Instruments time discoverer/server, foisted on me by an update to other software (from our principle) that blindly and stupidly updates ALL of the NI installed tools and utilities, causing other problems too, not just the lockups. Most tiresome. Now I've id'd the problem, I can work arround it. But as earlier, the info about the pool servers and (perhaps) not needing the location tags was good to know, though from what else I read, it's debatable if it will work reliably and predicably in practice for a traveling laptop. Thanks for the info and insight peeps. Regards. DaveB How critical is your time need? If it's within minutes, then the PC's clock is likely good enough. If it's in the UK or Europe, I would be surprised if pool servers did not get you well within the second - perhaps within 100msec - particularly if you set the servers based on the country you're in. I suspect that if you need closer than tens of milliseconds, carrying round a GPS 18x LVC (which I jokingly suggested) may actually be necessary. NTP was designed when connections were nothing like as good as they are now, and is supposedly robust in those circumstances. It is designed for 24-hours operation, though. 73, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] How to keep fake time in past/future?
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrnirnckd.qft.un...@wormhole.physics.ubc.ca... [] I still have no idea why the OP wants to do what he claims to want to do. Perhaps you remember how year 2000 rollover tests were carried out? It included setting the clock forward and seeing what happened. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Checking NTP status quickly
David J Taylor david-tay...@blueyonder.co.uk.invalid wrote in message news:iph27t$tsu$1...@dont-email.me... I have an application where it would be desirable to check that NTP is installed and running, and that the offset reported by NTP is within, say, one second. So we don't need millisecond precision, just to have a good idea that the PC's clock is correct within a second or so. I'm thinking that a mode-6 packet might do the job, but I have no experience with control packets. Is this the right way to go about things? Thanks, David Yes, it works, I found some old code with control-packet handling. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Checking NTP status quickly
Sorry, editing flub, the original message was at 13:18 UTC. At a minimum to accomplish your stated goal your code should ensure leap != 11 (that's normally displayed by ntpq in octal, so in Sorry, ntpq uses binary display for leap (and octal for reach). In both cases the on-wire form is decimal. Cheers, Dave Hart Noted, and I've passed that on. Creating a control packet (with no added buffer) is actually rather easy, and the reply is human-readable, plain text, which is most helpful. I will only need to monitor the offset and leap fields. I've passed on the information to the person who actually needs it, and we are both grateful for your time and replies. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP server with no network, no GPS signal
Hi! I am looking for a solution to install an NTP server in a very restricted network which can not be connected to other networks even through a firewall because of strict security policy. RS232 and usb are ok. Using GPS or DCF77 reference clocks would require a long antenna wire to get signal. Installing the antenna cable would be expensive, but there is good LAN cabling between a space with good GPS signal and the room with high security. What kind of cheap solutions would you think of? For instance, is it possible to feed time signal from one NTP server to another via RS232/usb? Or is there an affordable usb/rs232 reference clock which has an IP based separate antenna unit? With best regards, -- Cristian Seres Cristian, I would consider installing a GPS puck (such as the GPS 18x LVC or Sure Electronics board) in the antenna space, and use the LAN cabling to distribute the RS-232 signal with PPS from the GPS to your NTP server PC (or multiple PCs). If needed, you could use line drivers and receivers to improve the signal integrity on a long cable run, and to distribute the PPS component of the signal to multiple server PCs. https://buy.garmin.com/shop/shop.do?pID=223 https://buy.garmin.com/shop/shop.do?pID=27594pvID=14555 http://www.sureelectronics.net/goods.php?id=99 Example of use: http://www.satsignal.eu/ntp/Sure-GPS.htm Once you have one or two stratum-1 servers, the rest can be synced over the LAN to within a few milliseconds, if that's good enough. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] UK: Notice of Interruption to MSF 60 kHz Time and Frequency Signal
I have received the following: Notice of Interruption to MSF 60 kHz Time and Frequency Signal The MSF 60 kHz time and frequency signal broadcast from Anthorn Radio Station will be shut down over the period: 03 May 2011 to 13 May 2011 Each day including weekends from 07:00 BST until 22:00 BST The interruption to the transmission is required to allow maintenance work to be carried out in safety. The signal may be restored early if the work is completed early on any particular day. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP/Linux Machine Issue
Your client software is five years out of date, I suggest you update it. Red Herring. Not even worth updating for the security updates? The problem here is that the client system is running in a VM. Not mentioned in the original post, though! The OP wants to sync this client to his local time server (10.200.37.37). -- Steve Kostecke koste...@ntp.org NTP Public Services Project - http://support.ntp.org/ Then he might want to follow the advice of his virtual machine supplier. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTP/Linux Machine Issue
Dear Support, This is a newsgroup, there is no support as such. I have a NTP server, and configure clients on it. I am facing an issue that the offset is too much high so there a difference in the time between the client and the server, it is reaching 1 hour sometimes. NTP client version: ntpq 4.2.0a@1.1190-rmailto:4.2.0a@1.1190-r Thu Oct 5 04:11:36 EDT 2006 (1) Your client software is five years out of date, I suggest you update it. remote refid st t when poll reach delay offset jitter == 10.200.37.3785.91.1.180 3 u 35 64 170.898 1194.28 147604. *LOCAL(0)LOCAL(0)10 l 32 64 170.0000.000 0.004 Hope you can help me in that Yousif Qaddoura In your ntd.conf, remove the local clock, and add in three pool server lines such as: server 0.pool.ntp.org iburst server 1.pool.ntp.org iburst server 2.pool.ntp.org iburst If your alder NTP complains about the iburst, remove it. Be sure that your PC is fairly near correct time in the BIOS, and that the time zone is correct. Retry NTP. Please note that I run FreeBSD and Windows, not Linux, so the above advice may not be correct in its detail. Good luck, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Richard B. Gilbert rgilber...@comcast.net wrote in message news:ot-dnvdagogjoizqnz2dnuvz_o-dn...@giganews.com... [] Anyone who doubts the accuracy, legitimacy, etc. of pool services should be able to purchase a GPS timing receiver and get the time from the horse's mouth. The investment required is about $100 US at a minimum. Even less - US $34 now http://www.sureelectronics.net/goods.php?id=99 http://www.satsignal.eu/ntp/Sure-GPS.htm Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrnir4tou.j3t.un...@wormhole.physics.ubc.ca... [] He did say a timing receiver. That could mean a GPS receiver specifically set up to supply time, including an on board temp insensitive crystal to supply the time if the sattelite availability goes to low. .. and I don't think that the US $100 GPS 18x LVC claims to have that. Also it is $42 since you need to receive it, unless you happen to be visiting Hong Kong. And then you have to solder a few wires onto surface mount pins. .. but you don't need to pay US $100. Oh, and you do need to solder with the GPS 18X LVC as well. Personally, I am delighted with the choice of GPS/PPS receivers now available at very affordable prices, and welcome the choice. You pays your money and takes your choice. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Rob nom...@example.com wrote in message news:slrnir52mv.hnj.nom...@xs8.xs4all.nl... [] Why is this irrelevant discussion started every time some topic is being discyssed in this newsgroup? It does not matter what the initial question is, what problem someone tries to solve, what requirements he has, what limitations he may have, what possibilities there are in solving the issue at hand, there is always someone who brings up the #$%^@$@ GPS receiver and starts boasting the price it may be acquired for. Please people, please grow up. Rob, GPS/PPS is, perhaps, the most used reference source for stratum-1 clocks with NTP, so they are hardly irrelevant, and for the OP who wants reliable time when away from the office, a portable GPS receiver may be a candidate solution. For many folk, those paying out of their own pockets, the cost matters. Having said that, I have already made my suggestion to the OP based on what I do myself - to use NTP and the pool servers. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Rob nom...@example.com wrote in message news:slrnir54hp.hnj.nom...@xs8.xs4all.nl... [] The initial question: | Due to my wandering use of a laptop for, work (cough!) Often away | from the office, and our server, but with local internet access (Hotel | WiFi etc). | | What UK based RELIABLE (cant emphasize that enough) UK time server(s) | would the group recomend I point Windows time sync' to? and the subsequent discussion about the NTP pool and its reliability, and how many servers from the pool one would resonably use to get good results without overloading a voluntarily provided service, is a good and valid discussion on its own. There is no need to pollute that discussion by talking about GPS receivers yet again. It is not a solution for the original poster, and it does not contribute to the discussion about either of the topics brought up. You may be exited about your new GPS receiver toy, but there is no need to recommend that hammer as the only tool one will ever need. It isn't. .. and why shouldn't someone consider taking a GPS 18x LVC as a portable time reference? BTW: I did not start the GPS discussion. David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Roger invalid@invalid.invalid wrote in message news:oei2r6p2ut7793hu02pauutkjmm22ht...@4ax.com... On 21 Apr 2011 16:18:39 GMT, Rob nom...@example.com wrote: When I do a lookup of pool.ntp.org I get three addresses returned that are local to me. I'm in the UK and the three I just got were UK, France, and Bulgaria. Bulgaria is definitely not local; a traceroute took 18 hops and 71 ms. -- Roger Similar here - after changing to non-regional servers I saw France, Germany etc. and not one in the UK. Have reverted to 0.uk.pool etc. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Is your Internet provider a company that is also (or mainly) active in France and Germany? No, exlusively British, I believe. Apparently the IP location service misinterprets your IP adress. That should be fixed. For the addresses I can test it works flawlessly. My IP address is: 94.174.197.75, so perhaps that's recently allocated? Can you test it? Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
I hope that the pool folk will be able to update their page in due course - likely documentation isn't the top priority! The quickest way to bring this to their attention is to report it on the p...@lists.ntp.org mailing list. -- Steve Kostecke koste...@ntp.org Already done, Steve. BTW: is the e-mail to Usenet gateway for this Usenet group working properly? I ask as I've had a couple of e-mails which I've not seen on Usenet. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Rob nom...@example.com wrote in message [] server 0.uk.pool.ntp.org iburst server 1.uk.pool.ntp.org iburst server 2.uk.pool.ntp.org iburst server 0.nl.pool.ntp.org iburst server 1.nl.pool.ntp.org iburst Omit the region codes (uk, nl etc). They are no longer required and when you are mobile you should not have them. The pool.ntp.org dns determines where you send your request from and returns servers that are local to you. However, Rob, the Pool Web pages suggest that better results will be obtained by leaving the country codes in: http://www.pool.ntp.org/en/use.html Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntp server specs
Richard B. Gilbert rgilber...@comcast.net wrote in message news:wegdnew3j4a37tlqnz2dnuvz_gwdn...@giganews.com... [] You don't really care what hardware the server runs on! X86 should work as well as any other architecture. The software is somewhat more important. Linux works well on the X86 platform and could reasonably be used as an NTP server. Windows on X86, or anything else, is not nearly as good a time keeper, as Linux, Unix, OpenVMS and perhaps others. NTPD does not place a heavy load on most modern hardware; you should never notice that it's there unless you go looking for it. Completely agree on the software. The best OS for NTP is generally considered to be FreeBSD. Even if you have to use Windows with a GPS/PPS reference you can get within 250 microseconds or better - see PCs Feenix, Stamsund and Alta here: http://www.satsignal.eu/mrtg/performance_ntp.php The FreeBSD system is PC Pixie. Keep away from anything which causes the CPU speed to vary, such as power-saving or spread-spectrum. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Using two NTP Server: Bad?
Ben Rockwood b...@cuddletech.com wrote in message news:4daf84fc.7060...@cuddletech.com... I've read in the past that clients should always have an odd-number of NTP servers; 1 server or 3 servers but not 2. If I recall the reason was that clients could become confused and needs a tie breaker. Question 1: I want to challenge this old assumption. Is there truth to it? In many environments there is a desire to have 2 NTP servers for redundancy purposes, but not 3 due to limited resources. If you have three servers, and one fails, which of the two remaining servers do clients believe? You can configure your clients to have as many servers as you want, but perhaps 4 is the minimum, and I have seen five and seven suggested. Of course, depending on your application, it may be acceptable that some of the servers are not as accurate as others so you could have just one or two local servers, and three Internet servers configured on the clients. Question 2: Furthermore, if you have 2 local NTP servers is it preferable to have them sync off of different sources to avoid a client syncing servers that are using the same reference clock? ie: Is this bad?: [] Thank you. benr. In that situation, I would agree with Chris Albertson and get two GPS receivers - they are now quite cheap (e.g. about US $35 including the antenna) so you could perhaps have two in different locations depending on your network and buildings. If the servers are syncing from the Internet, I might have them with a configuration including, say, four pool servers, plus one good local server marked as prefer, but a different local server in each case. A server offering a good public service, such as Manchester and Glasgow in the UK. Just some ideas. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Hi David. Long time no speak. Oops, I missed the callsign! Hope all is well. I'd ordinarily love to, but this is the works machine I carry arround places etc. Our illustrious IT droids have no interest in this, other than to Flatten the machine and re-install the OS. Anything outside the normal Office apps and regular OS issues, they have no knowlege of. Heck, I've fixed more IT problems round here than they ever will, (but I don't go near the office server!) Cheers. DaveB. I might even take the view that your illustrious IT droids aren't doing their job properly if they aren't taking an interest in timekeeping to the extent of replacing W32Time by NTP in their standard install procedure! G Perhaps timestamps of actions aren't critical your organisation. I hope you may be able to convince them in due course. Having said that, I've not seen W32Time causing a crash, but my first step might be to rename the appropriate branches of the registry to try and make W32Time recreate them from scratch. 73, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Rob nom...@example.com wrote in message news:slrnir0cq8.7do.nom...@xs8.xs4all.nl... [] However, Rob, the Pool Web pages suggest that better results will be obtained by leaving the country codes in: http://www.pool.ntp.org/en/use.html The documentation is outdated. I would have hoped that the pool folk kept their documentation up-to-date, so I'll post that on their list. You didn't mention how to control the number of servers uses - is it just multiple pool entries? Thanks, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Rob nom...@example.com wrote in message news:slrnir0m6v.e7e.nom...@xs8.xs4all.nl... [] I don't know how the pool functionality in ntpd works, it is not available in the version I use. Thanks, Rob. Perhaps there is a page somewhere? I only know that the pool has introduced a location-aware DNS some time ago, and that the documentation is not really uptodate. The paragraph in question still assumes that pool.ntp.org returns random servers from all over the world. It no longer does that. When I do a lookup of pool.ntp.org I get three addresses returned that are local to me. How many server entries that will give with ntpd I don't know. I hope that the pool folk will be able to update their page in due course - likely documentation isn't the top priority! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Hi All. [] At least, looking in the system error and info logs, after recovering from a lockup, it's related to W32Time going bad, not long after first boot of the day. [] Idea's brickbats etc welcome... Regards. DaveB. Dave, Forget W32Time and use NTP exclusively. I have it on the portables here, which I've used throughout the UK and world-wide. You can see the world-wide entries commented out with the # symbol. Install guide: http://www.satsignal.eu/ntp/setup.html Sample configuration: __ server 0.uk.pool.ntp.org iburst server 1.uk.pool.ntp.org iburst server 2.uk.pool.ntp.org iburst server 0.nl.pool.ntp.org iburst server 1.nl.pool.ntp.org iburst # server 0.asia.pool.ntp.org iburst # server 0.no.pool.ntp.org iburst # server 0.south-america.pool.ntp.org iburst __ Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
Omit the region codes (uk, nl etc). They are no longer required and when you are mobile you should not have them. The pool.ntp.org dns determines where you send your request from and returns servers that are local to you. Thanks for the suggestion, Rob. Implemented. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Windows time question.
The more recent versions only _need_ one pool line, and it will keep pulling up more servers as needed. -- E-Mail Sent to this address blackl...@anitech-systems.com will be added to the BlackLists. Thanks for that reminder. I'm running ntpd 4.2.4p6 on that particular PC. Does that support the one pool line option? How does it know whether to use 4, 5, or seven servers? I take it you mean the pool rather than the server configuration line. Do you perhaps have an example? Thanks, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTPD can take 10 hours to achieve stability
Thanks for all the great answers. Now for a harder question, how does the accuracy of the local clock source affect the accuracy of ntpd. Thanks Chip Chip, It also depends on the OS in use. Even with a timekeeping GPS (better than a microsecond), Windows does not keep time as well as FreeBSD. Compare FreeBSD: PC Pixie, Windows: PCs Feenix Stamsund http://www.satsignal.eu/mrtg/performance_ntp.php In my experience, even given an accurate source (e.g. a PC syncing to a FreeBSD stratum-1 server), the network performance may have a greater influence that the performance of the reference clock, especially if that network contains gigabit components, or off-site connections, wireless, ADSL etc. If you want the best accuracy, ensure your PCs have a serial port, and pipe a pulse-per-second signal round your lab. NTP works well with that. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTPD can take 10 hours to achieve stability
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrniqpa40.ppu.un...@wormhole.physics.ubc.ca... [] Well, I think someone other than the current maintainers will have to port it to windows. Since windows timekeeping is not the worlds best anyway, it is probably true that the extra accuracy of chrony is unnecessary. It does have a command line option like ntpq -p provided by chronyc (depending on what you mean by like). What MRTG is I do not know. If you are happy with ntpd, by allmeans stay with it. A pity that chrony will not be offered for Windows, at least for tests to see whether it lives up to its claims. There are times when a more rapid convergence would be welcome, such as the reboot of PC Molde around 13:30 yesterday: http://www.satsignal.eu/mrtg/molde_ntp-b.html MRTG is a standard logging tool for network I/O which uses SNMP to produce the graphs I have quoted here many times for network throughput and timekeeping: http://www.satsignal.eu/mrtg/performance_network.php http://www.satsignal.eu/mrtg/performance_ntp.php I've written how to extend MRTG to monitor NTP timekeeping, and various other parameters such as disk space and temperature here: http://www.satsignal.eu/ntp/NTPandMRTG.html http://www.satsignal.eu/mrtg/performance_howto.php From chronyc I would need to be able to use a simple Perl script to extract the numbers to be plotted - such as the Offset in the graphs above. An easy job if the format is standardised and machine readable. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTPD can take 10 hours to achieve stability
David Woolley david@ex.djwhome.demon.invalid wrote in message news:iojbue$ge9$1...@dont-email.me... [] As I keep saying, offset does not accurately measure time keeping accuracy. A low offset can mean that you are tracking traffic variations on the LAN, or interrupt latency variations, rather than local clock frequency variations. It is also a pessimistic estimate of accuracy when everything is locked up and stable. David, Unfortunately, there are a limited number of variables NTP exposes. If there's something better, please let me know. What be ideal would be offset of this PC from true UTC. Thanks, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTPD can take 10 hours to achieve stability
C BlacK rb...@non.net wrote in message news:o-adnvwgbzb3ntbqnz2dnuvz_ocdn...@supernews.com... Why would it take ntpd ten hours to achieve its accuracy? Can this be explained in laymans terms and mathematically What accuracy do /you/ want? For best accuracy which NTP can achieve, in the order of microseconds or better, your PC may need to be in a temperature controlled environment - how long would it then take to stabilise its own temperature? Compare people using the best frequency sources, who may need to leave them for days to achieve their best accuracy. On the other hand, if all you need is, say, 20ms (the clock interrupt period on many Windows PCs, so as accurate as a typical program could measure) then NTP might be that accurate just as soon as you've logged in. The time taken to stabilise will typically depend on what accuracy /you/ want to achieve, so ten hours alone is meaningless out of context. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTPD can take 10 hours to achieve stability
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrniqnml8.ln1.un...@wormhole.physics.ubc.ca... On 2011-04-18, David J Taylor david-tay...@blueyonder.co.uk.invalid wrote: C BlacK rb...@non.net wrote in message news:o-adnvwgbzb3ntbqnz2dnuvz_ocdn...@supernews.com... Why would it take ntpd ten hours to achieve its accuracy? Can this be explained in laymans terms and mathematically What accuracy do /you/ want? For best accuracy which NTP can achieve, in He was refering to the statement that ntpd can take up to 10 hr to achieve its accuracy. That is the time taken for ntpd to settle down to an accuracy of a few usec if they start off with a few 10s of PPM in rate error. So, there is an implicit accuracy related to that 10 hour statement, which may not apply to someone else's needs. the order of microseconds or better, your PC may need to be in a temperature controlled environment - how long would it then take to No. With a GPS clock, ntp will run with a few usec error ( about 3-5usec) even in a non-temp corrected environment. But it is clear looking at the errors that it is because ntpd takes so long to settle down that is dominating the errors. Mine is within about 6 microseconds, in a non-temperature controlled environment (running 24 x 7). Looking at the plots it is quite clear that temperature variations are the limiting factor in accuracy, and not NTP. stabilise its own temperature? Compare people using the best frequency sources, who may need to leave them for days to achieve their best accuracy. On the other hand, if all you need is, say, 20ms (the clock interrupt period on many Windows PCs, so as accurate as a typical program could measure) then NTP might be that accurate just as soon as you've logged in. Yup. that is certainly true. If all you want is a few ms, then ntp will settle down in a few hours. (See the graph at the bottom of www.theory.physics.ubc.ca/chrony/chrony.html where ntpd started off with with a rate error of 40PPM and took a few hours to settle down to a few ms accuracy.) Then it could be that you may not not seeing the best which NTP can achieve, if you need to wait a few hours rather than a few minutes. The systems running here, those which are not running 24 x 7, are typically already within few ms after booting up, when you log in. Not always, but very often. For example: http://www.satsignal.eu/mrtg/performance_ntp.php PC Narvik has just been rebooted (09:35 UTC), and is within 0.25ms. PC Puffin was switch on at about 04:30 UTC after being off overnight and was within about 0.5ms. These are LAN-synced systems, running Windows, and tuned for that environment. You would likely not achieve the same either ultimate accuracy or settling time when working from a set of Internet servers, or you have an unfortunate combination of OS, motherboard, application set, or CPU power-saving activation. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTPD can take 10 hours to achieve stability
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrniqotoj.40a.un...@wormhole.physics.ubc.ca... [] Mine is within about 6 microseconds, in a non-temperature controlled environment (running 24 x 7). Looking at the plots it is quite clear that temperature variations are the limiting factor in accuracy, and not NTP. No, it is ntpd. It is because ntpd is so slow to respond to errors that and it takes so long to correct for those temp changes, that the accuracy is what it is. (That and ntp's behaviour of throwing away 80% of the data it collects). I would be quite willing to test a fast-response option in ntpd to see whether it makes nay difference. IF your file has the correct drift information in it (linux for example with the tsc clock changes its drift about 40PPM on each bootup) and if it has not been very long since the machine was switched off, then yes, it will be accurate very fast. Those are big ifs. The question is how long does it take ntpd to recover from errors. The figures I gave above give you a clue. chrony is at least an order of magnitude faster. Well, if Linux is that badly behaved (altering its clock on each boot), I would have said that was an OS defect which needed correction, not altering ntpd to accommodate faulty software! For me, performance under normal use is probably more important than performance under error conditions. When chrony has a Windows version and provide a similar command-line ability to ntpq -p for getting performance data into MRTG I would consider testing it on a client PC here. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Sure GPS: Programming it now works
I've written a tiny program to do exactly this and this is the output: [] BTW, this morning I got 14 sats in the (4!) GSV messages, that's the first time I've seen a GPS with info about more than 12 sats! :-) Terje Terje, That's great! Any chance of a copy of the program? Did you ever resolve the failure to hold programmed baud rate issue? Thanks, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Sure Electronics GPS board: Amazing performance. :-)
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrnipci4i.3la.un...@wormhole.physics.ubc.ca... [] Which route did you take-- PPS pin to RS232 (CMOS level) or via the buffers/inverters? All I am pointing out to people who might regard the sure board as a really cheap path, but do not have the soldering skills is to beware. If anyone feels that they can solder to surface mount devices, and have the tools (really fine, temp controlled soldering iron), go for it. It is a cheap way of getting accurate time. And the usb power in and NMEA output are really nice. I used the inverter and RS-232 level convertor route, as shown on my Web site: http://www.satsignal.eu/ntp/Sure-GPS.htm The two wires required are clearly shown. Certainly if you (or a friend, or a workplace or local TV repair shop) don't have skills or soldering equipment, it's not a project for you, but you don't need special surface-mount soldering equipment. A little care and fine soldering tip are required. Any one who might be interested can look at: http://www.satsignal.eu/ntp/sure-GPS-top-modification.jpg and make their own judgement. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Sure Electronics GPS board: Amazing performance. :-)
I've done some more careful inspection of the Sure GPS comms trace: It really looks like the GPS does _not_ listen to commands by default, instead the controlling program sends a solitary '0' char to ask for permission to talk. About 200 ms later the GPS boards drop the CD (Carrier Detect) line, and then the gps.exe program sends the private NMEA message. As soon as the ending CRLF arrives the GPS turns CD back on and restarts the configured NMEA messages. If this sequence is required by default, then it must also be possible to turn off such very non-standard GPS behavior, right? Terje Fascinating! I wonder whether that GPS chip is really intended for talking to a on-board microprocessor, and we're seeing the raw behaviour? As the board can forget any baud rate changes (although NTP works correctly at the default 9600 baud), perhaps it might forget any programming changes as well? Presumably, you didn't get the programming manual as yet? Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Sure Electronics GPS board: Amazing performance. :-)
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrnipapga.co8.un...@wormhole.physics.ubc.ca... [] Using a soldering iron on surface mount devices is a bit trickier-- too easy to bridge the pins is you do not have very steady hands. Not saying you cannot do it. But Joe Bloggs might have more trouble. I would certainly /not/ count myself as one who is able to solder surface-mount devices, I don't have the tools required for one thing. But in this case you are soldering to the device leads, which are over 1mm apart, so it's not too bad. Just take a little care, and be sure to use a fine tip. You could even try sending the CMOS-level signal down the RS-232 cable, and then it's just regular soldering, no connections to devices required. I've done a couple of these boards now, and the soldering isn't an issue. I'm over 60, by the way. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] UK - GPS Jamming update
The MoD has informed Ofcom of the following GPS jamming exercise update: Reference: JRS0012 Dates and times: GPS jamming will take place according to the following schedule: 6 Apr 1400-1500Z 8 Apr 0200-0400Z 1000-1100Z 1330-1530Z 2000-2359Z 12 Apr 0800-1000Z 2200-2359Z 13 Apr 1400-1600Z 2100-2200Z 14 Apr 0100-0300Z 0800-0900Z Location: GPS jamming will take place from Loch Ewe (N57° 51.9' W005° 41.1'). __ Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Sure Electronics GPS board: Amazingperformance. :-)
I'd have to say the Motorola Oncore UT+ is the easiest to use. All the connections are to 0.1 pitch male header pins so there is no need for solder. The UT+ sells for about $16 on ebay. The documentation is exhaustive and complete and written in standard English. And of course the UT is very accurate with a standard deviation in the PPS of about 49 nS. The newest version of this GPS is the M12M sold by Synergy Systems. It sells in qty 1 for $60 and comes with tech support from a US company and has PPS arcuate at the 2nS level. I'll buy this one next I don't think the dps18 comes even close to 2ns. Here is the data sheet. http://www.synergy-gps.com/images/stories/pdf/m12mt_brochure.pdf -- = Chris Albertson Redondo Beach, California The Sure was considerably easier to use, for me. It comes with a USB lead, so that's the +5V power done, and a serial connector right on the board. As accurate as any of the PCs I have. It includes the GPS puck antenna as well. Not bad for US $34 (about one third of the price of the Garmin GPS 18x LVC in the UK. We are spoilt for choice! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Odd offset for PPS DCD w/ Garmin GPS 18x LVC
Thanks to all. I am using Garmin 3.20, as it it turns out. However, I reverted to 4.2.5p233 of Dave Hart's builds, and it does not appear to have the same strange behavior. I had been using 4.2.7p138 (which I first installed only yesterday). I'll try a few of Dave's other builds to see if I can see where the boundary is. I don't know how he numbers his builds so I don't know whether this build is thought to be stable or not. It was only built a few weeks ago. Thanks again. I, for one, will be most interested in your results, Larry. stable builds have even numbers development have odd numbers I believe some of the later changes relate to how multiple NMEA sentences are handled, but I can't give you exact version numbers where changes were made. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntpd -q and driftfile
Hi, I would like to know if ntpd would use the driftfile specified in /etc/ ntp.conf file if it is run periodically using crontab with -q option as below: /usr/sbin/ntpd -u ntp:ntp -p /var/run/ntpd.pid -g -q -L eth0 I do not find any drift file being created at the specified location. Thanks and Regards, Prashant Prashant, ntpd is intended to for continuous, not periodic running. You are not using it correctly. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntpd -q and driftfile
He can do that if he wants to. That was why the -q option was designed into ntpd-- one time setting of the clock time. However it cannot create a drift file. If he wants a drift file then as you say, he must run it continuously. You could look at it that way, Bill, if all he needs is a one-off setting. However, Prashant says he wants to run it periodically, which doesn't really make sense. Rather than a periodic run, he should leave ntpd running continuously, which is what ntpd is designed for. Prashant, the fact that the server capability is already built-in to ntpd in no way detracts from using ntpd just as a client for your PC to keep the time spot-on. Just leave it running all the time as it uses very little resources. It will then compute the drift information after (IIRC) one hours of running, and it will keep your PC clock correct by adjusting the rate, rather than bang-bang adjustments of the time. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] GPX18x LVC 3.50 firmware - high serial delay problem workround
Q ..@.. wrote in message news:4d887390$0$2524$da0fe...@news.zen.co.uk... [] Hi David, A reply from Garmin! Also I tried the downgrade - its in and working, though I'm not seeing much if any difference in the numbers yet - I should be able to post some data later in the week once its calmed down. Well, that's good, it means one more report into Garmin, and increases the likelihood of a fix. From my tests on a Sure GPS board, it many be important to get NTP to look for the first sentence sent, although I guess you must already be down to a single NMEA sentence by now. It may be worth trying 115,200 baud as well. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Odd offset for PPS DCD w/ Garmin GPS 18x LVC
lellis larry.el...@gmail.com wrote in message news:efc6e755-c213-4a10-90f9-420384001...@s18g2000prg.googlegroups.com... On Win XP, I am seeing an odd positive offset of about 128ms on the Atom driver, relative to other sources: remote refid st t when poll reach delay offset jitter == *GPS_NMEA(1) .GPS.0 l6 16 3770.000 0.373 0.919 xPPS(1) .PPS.0 l5 16 3770.000 125.447 0.830 -clock.team-cymr 172.16.65.22 2 u 39 64 77 12.989 -41.044 44.960 +ntp.okstate.edu .USNO. 1 u 42 64 77 28.906 -18.762 25.784 +navobs1.wustl.e .GPS.1 u 38 64 77 19.133 1.819 19.599 Normally, I just use NMEA with fudge, but that was also showing the odd offset so I removed fudge and added the Atom driver to help debug this. (Normally the status shows oPPS(1) but xPPS(1) is seen above for the obvious reason. ntpd is Dave Hart release 4.2.7p138; I have a serialpps-ppsapi- provider.dll dated 6/6/2009. Any ideas or recommendations. Larry, You may want to revert to the 3.20 firmware for you GPS 18x LVC - see what others have written: http://support.ntp.org/bin/view/Support/ConfiguringNMEARefclocks#Section_6.1.12.2. http://support.ntp.org/bin/view/Support/ConfiguringGarminRefclocks and there is a somewhat flawed analysis here: http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm#gps-18x (flawed in that I was being helped by a UNIX person, and the Windows driver does not work in exactly the same way as we had assumed). Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntpd -q and driftfile
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrniohmmc.6v5.un...@wormhole.physics.ubc.ca... [] ntpd -q is a replacemtn for ntpdate, which was typically run from cron, and he is doing, and it is an acceptable procedure if for example you do not want a daemon running which could have (unknown to you) security issues. It is also a bit unclear how to switch off the server role of ntpd and he may not want others querying his machine. On the other had it comes at a cost of far worse clock discipline and the probability of the computer jumping backwards in time. For a one-off invocation, acceptable, but to use it for repeated periodic invocations would require further justification, in my view. One hour? More like 10 hr. ntpd is really bad at recovering from changes, and switchon is a big change. After 1 hr the drift is liable to be way off, as ntpd alters the drift to bring the clock back into line. In my experience, NTP writes the drift file every hour, not every ten hours. Even after one hour, the drift value is likely to be of more use than no drift value at all. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] GPX18x LVC 3.50 firmware - high serial delay problem workround
Q ..@.. wrote in message news:4d88df4c$0$2514$db0fe...@news.zen.co.uk... [] If you have no objections it may be easier to take this 'off-list' and email you direct - it will save all the poor folk on here having to listen to my insane testing - once everything is working and playing nice I can post back. Let me know if this is OK and I'll drop you an email later this evening. I would prefer on-list, as others may be able to provide help and useful input. I'm not sure I can add more than is already on my Web pages. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntpd -q and driftfile
unruh un...@wormhole.physics.ubc.ca wrote in message news:slrniohsae.ksv.un...@wormhole.physics.ubc.ca... [] I have seen the drift out by 400PPM at around the hour mark. ntpd massively overswings to correct any intial error in the clock ( say a few ms) , and then gradually settles back toward the correct drift rate. Thus the drift printed into the file during that transient really has little relation to the true drift rate, and is not very helpful. I have seen the drift become unstable, but not after just starting ntpd, and not recently. Perhaps there was a bug which is now fixed? Now, if the clock is close to the correct time, and the system had a reasonable drift rate in the file before hand, then the drift rate published after an hour may well be pretty close to the right rate. But if the clock was say out by 50ms, then it could get pretty hairy. This problem is caused by ntp having no memory, except for the drift rate and the current time. It thus cannot use the past history of offsets to make a better estimate of what the true drift rate is. The drift rate it has now is a sum of the true drift rate and the drift rate being used to correct the clock offset. While with history, it would be trivial to calculate the true drift rate and disentangle the two ntpd does not do that. (chrony does). Perhaps if is the operative word here - I have not seen this to be a problem on my systems within the last year or two, and they aren't rebooted very often. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] 64-bit serialpps.sys despite unsigned?
Which apparently allows ongoing, hands-off use of unsigned drivers after initial setup. I am curious to hear from anyone who tries it with serialpps.sys and ntpd on Windows. Cheers, Dave Hart Folks, This is now written up here - comments and corrections warmly invited: http://www.satsignal.eu/ntp/NTP-on-Windows-Vista.html By using /both/ the kernel-mode driver, /and/ enabling interpolation, averaged jitter on this system has been reduced from over 1.5 milliseconds to under 40 microseconds. Not often you get an almost forty-times improvement for a couple of hours work! My thanks to Dave Hart for his Windows support, the modified serial driver, and for discovering how to use unsigned drivers! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] ANN: UK - GPS jamming - 2 May 2011
Coming thick and fast! _ The MoD has informed Ofcom of the following GPS jamming exercise: Dates: 19 - 26 May 2011. Times: limited periods between 0700z 19 May to 100z 2 May 2011. Location: The ground based radar jamming events will take place in the SW approaches against the remote radar head at Portreath 21-22 May, undertaken by F-18 Growler aircraft. Additionally there will be radar jamming against deployed targets in South West Wales throughout the period 19-26 May. Communications and airborne radar jamming will take place throughout the same period on the East Coast with aircraft operating within the North Sea Military Danger Areas. Communications and maritime unit radar jamming will take place in the SW approaches and Bristol Channel. Falcon aircraft will operate from Sea Level to FL240 unless jamming AEW aircraft where they may operate above FL245. _ Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] 64-bit serialpps.sys despite unsigned?
Which apparently allows ongoing, hands-off use of unsigned drivers after initial setup. I am curious to hear from anyone who tries it with serialpps.sys and ntpd on Windows. Cheers, Dave Hart I'll try this out later today, Dave. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] 64-bit serialpps.sys despite unsigned?
http://www.ngohq.com/home.php?page=dseo Which apparently allows ongoing, hands-off use of unsigned drivers after initial setup. I am curious to hear from anyone who tries it with serialpps.sys and ntpd on Windows. Cheers, Dave Hart http://www.davehart.net/ntp/refclock/serialpps-20090606.zip Dave, I have tried this, with some success. I used your: serialpps-20091228.zip - the install.bat file altered the registry, but I got a file not found on .sys file, so I copied it by hand. - setting Windows to test mode, and test signing the copied driver worked. - I set the environment variable OK After a reboot, NTP appears to be working with the new driver, but the jitter is showing the 0.977ms expected /without/ QPC timestamping, rather than values less than 0.030ms I have seen on the 32-bit Windows-7 system. Here are extracts from the billboards: 64-bit: remote refid st t when poll reach delay offset jitter == oPPS(1) .PPS.0 l8 16 3770.000 -0.848 0.977 +GPS_NMEA(1) .GPS.0 l 13 16 3770.000 -1.315 0.977 *pixie .PPS.1 u28 3770.130 -0.954 0.977 +feenix .PPS.1 u 30 32 3770.009 -1.071 0.977 +stamsund.PPS.1 u 22 32 3770.002 -1.039 0.977 32-bit: remote refid st t when poll reach delay offset jitter == oPPS(1) .PPS.0 l 11 16 3770.000 -0.009 0.028 GPS_NMEA(1) .GPS.0 l 12 16 3770.000 -0.039 0.018 +feenix .PPS.1 s 14 32 1250.336 -0.056 0.477 *pixie .PPS.1 u 17 32 3770.2870.045 0.027 So while the test-mode signed driver on Win-7 64-bit works, it seems that the high jitter level I saw when testing PPS without the Atom driver on the same system remains. I had meant to write a small program to check the granularity of the QPC counter on that system but I've not had time so far. I can't imagine that QPC doesn't work on Win-7 64-bit, though. The time keeping performance can be seen here - but leave a few hours (say until 09:00 UTC) to make a judgement. http://www.satsignal.eu/mrtg/alta-ntp-b.html Please let me know if you want further tests, and if you wan to take this off-group. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] 64-bit serialpps.sys despite unsigned?
Which apparently allows ongoing, hands-off use of unsigned drivers after initial setup. I am curious to hear from anyone who tries it with serialpps.sys and ntpd on Windows. Cheers, Dave Hart It's certainly working, Dave, and that's great news! Compare the plot of PC Alta from 07:30 UTC this morning when the 64-bit PPS was installed: http://www.satsignal.eu/mrtg/performance_ntp.php Having the kernel-mode has provided a major improvement in the noise on the offset, frequency and jitter plots. However, it doesn't seem to be working anything like as well as nominally the same software installed in 32-bit Windows on PC Stamsund. Compare the offsets of 32-bit PC Stamsund (well under 50 microseconds) with 64-bit PC Alta (well over 500 microseconds and somewhat periodic). Looking in more detail, the offset as reported by NTP is varying from approximately -0.4ms to +0.4ms with a period of about 1.62 minutes (~97 seconds). That particular PC does have a very tight lock to another PC (server with max poll = 8 seconds), so I'll drop that back to 32s like the other servers and see if it makes any difference. Changed at 12:30 UTC. I'm not expecting to see a difference, but one never knows! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] 64-bit serialpps.sys despite unsigned?
Yes, it looks good, and thanks for clarifying the before was using the user-mode PPS hack in the Windows port of ntpd. However, it doesn't seem to be working anything like as well as nominally the same software installed in 32-bit Windows on PC Stamsund. Compare the offsets of 32-bit PC Stamsund (well under 50 microseconds) with 64-bit PC Alta (well over 500 microseconds and somewhat periodic). [] My guess: the key difference is the one you already identified, Stamsund is using a precision around -20 (microseconds) while Alta is stuck with precision -10 and the resulting minimum 0.977 ms jitter. If you manage to get Alta's system clock to tick 64 times per seconds instead of 500, 1000, or 2000 times per second, the interpolation code can correctly correlate the high-resolution counter and system clock given the 1000 Hz scheduler resolution. Things to try would include remove -M from ntpd options, prevent Flash or Java or media player apps from being run. Cheers, Dave Hart Dave, Looking in even more detail, I found that PC Stamsund had set, from 2009 Aug 23: NTPD_USE_INTERP_DANGEROUS=1 PC Alta had set, from 2010 Dec 19: NTPD_USE_SYSTEM_CLOCK=Yes I should have seen that before! Removing the system_clock and adding the interp_dangerous from Alta has resulted in an immediate improvement. Thanks for encouraging me to look further! Case solved (I hope) and 64-bit PPS working on Windows-7. My thanks for your work on this. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] ANN: UK GPS jamming exercises 10-21 July 2011
Folks, I have received the following announcement: ___ The MoD has informed Ofcom of the following GPS jamming exercise: Dates: Jamming will be conducted on a maximum of 3 week-days in the period 10-21 July 2011.Times: 0900 -1730 BST. Location: Jamming aircraft will orbit at 10,000ft above mean sea-level (AMSL) along a 50nm flightpath on a heading of 270°T from Kirkwall, starting 10nm to the west of Kirkwall and ending 60nm to the west of Kirkwall Possible areas affected: The GPS jamming is likely to affect civilian Standard Positioning Service (SPS) receivers over a large area. A minimum jammer to signal vulnerability of 30dB has been assumed for a civilian receiver. Signal theory suggests that a SPS civilian receiver should have approximately 32dB of jamming resistance. Safety of Life Operations: Safety of life operations will take precedence over exercise activities at all times. To this end, the AWC is open to further discussion with any official recipient on the potential implications of this jamming exercise. ___ (Contact telephone numbers removed) David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] GPX18x LVC 3.50 firmware - high serial delay problem workround
Q ..@.. wrote in message news:4d7fd7ae$0$2503$db0fe...@news.zen.co.uk... David J Taylor david-tay...@blueyonder.co.uk.invalid wrote in message news:ilc6um$4s8$1...@news.eternal-september.org... To me it should be common courtesy to reply as soon as possible, even if it's just an acknowledgement. You might learn more from a phone call Still no reply - but I've not had time to call them up yet and start making a noise. Do you have a copy of the old firmware - and is there any reason not to downgrade? No reason not to downgrade, Q, if you don't need the fixes and features in the current firmware. I understand that some folk are running on firmware 3.20, Yes, I do have copies, but you can also download here: http://www.gawisp.com/perry/oem_sensor/ Specifically: http://www.gawisp.com/perry/oem_sensor/GPS18xPC_LVC_320.exe Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Flash 400 on all peers; can't get ntpd to be happy
Is that NT3.5 fact still valid ? Never understood why anyone would use Windows for real work anyway. The thing that it does best is waiting ever faster for the next keypress from the user. uwe Perhaps people use Windows because the software they wish to run is only available for Windows? I know that two reasons I develop for Windows are that my customers want Windows software, and I don't need to create half a dozen different versions for the variants of UNIX-style OSes which are out there. But I also use FreeBSD and Apple's IOS where they are more appropriate. Oh, and for many people, their interaction with Windows is not mainly via the keyboard. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Flash 400 on all peers; can't get ntpd to be happy
Uwe Klein uwe_klein_habertw...@t-online.de wrote in message news:h01s48-89b@klein-habertwedt.de... David J Taylor wrote: Is that NT3.5 fact still valid ? Never understood why anyone would use Windows for real work anyway. The thing that it does best is waiting ever faster for the next keypress from the user. uwe Perhaps people use Windows because the software they wish to run is only available for Windows? I know that two reasons I develop for Windows are that my customers want Windows software, and I don't need to create half a dozen different versions for the variants of UNIX-style OSes which are out there. But I also use FreeBSD and Apple's IOS where they are more appropriate. Look at how x-platform OSS software can be without much hassle. Best organised example : Debian imho. Getting no traction cross distribution but on the same CPU family is nearly 100% attributable to not understood dependency and build processes. Same with all the display and usability problems Adobe has on linux. Big mouth and a long list of what linux lacks. But OSS software invariably does not have the issues while not lacking in performance either. Oh, and for many people, their interaction with Windows is not mainly via the keyboard. you mean they only do click and drool ;-) Cheers, David G! uwe Uwe, I will not discuss this further with you as it's veering off-topic here. Suffice it to say I am happy to live and let live, and take advantage of the best features of each OS I use without feeling the need to insult others who may have different needs. I will say a very big THANK YOU to those who have ported NTP to the different operating systems, and spent a lot of their own time working round the differing challenges this provides. For my own part, I have done quite a bit of testing, provided tools to help monitor and manage NTP, and published my findings to help others. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Autokey sequence error
Versions: System is debian Lenny, ntp is version '1:4.2.4p4+dfsg-8lenny3' I've followed the rabbit hole as far as I can. Can someone point me in the right direction from here? Martin, I don't know whether it will help, but the current stable version of NTP is now 4.2.6p3, form: http://www.ntp.org/downloads.html Perhaps there is a bug fix - it might be worth checking. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Autokey sequence error
Thank you for your answer. Yes, that was something I considered. However, there is no newer Version in lenny-backports, and I have shied away from building it myself (additional error potential and all that.) Anyway, I just found my mistake: [] Thank you for your help! Considering I know nothing of autokey and next to nothing about Linux, I'm delighted to have helped! Glad you are further along the road now, Martin. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] GPX18x LVC 3.50 firmware - high serial delay problem workround
Q ..@.. wrote in message news:4d79277a$0$2538$da0fe...@news.zen.co.uk... David J Taylor david-tay...@blueyonder.co.uk.invalid wrote in message news:il7bhl$vgg$1...@news.eternal-september.org... I hope that Garmin at least acknowledge your request - let's hope the delay means that it being passed on. Nothing yet - not even a robot responder telling my the form had been logged... I'm tempted to try and call them tomorrow, but I don't know how that might go. To me it should be common courtesy to reply as soon as possible, even if it's just an acknowledgement. You might learn more from a phone call Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] GPX18x LVC 3.50 firmware - high serial delay problem workround
Hi David, I sent off the query/problem to them a few days ago via the online form - alas no reply as yet though. I've had problems my end anyway the box this is attached to decided to die and I had to replace the CPU which did all sorts of odd things with the clock and required a change of timer source to stop the thing running mad. It's taken a couple of weeks for it to sort its self out and the jitter/offset to come back down to what they where. Anyway if I hear anything back I'll post here. I hope that Garmin at least acknowledge your request - let's hope the delay means that it being passed on. Sorry to hear about the box problems - I replaced my Pentium 133 system with a fanless Intel Atom system when that happened. The 18x is now being used just as a PPS reference on my Windows-7 SP1 system (and I think SP1 has stopped the glitches I used to see, so better timekeeping), with the NMEA part set to noselect: # PPS serial port driver - uses serialpps.sys server 127.127.22.1 minpoll 4 # PPS using serialpps.sys # NMEA serial port driver server 127.127.20.1 minpoll 4 mode 33 noselect # 19200bps, NMEA serial port Checking further, before SP1 averaged jitter was 22 - 80 microseconds, and after SP1 18 - 28 microseconds, so Windows-7 SP1 has helped the timekeeping. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Flash 400 on all peers; can't get ntpd to be happy
Ralph ra...@depth.net wrote in message news:c5b90638-395f-4e77-8761-f99c25343...@glegroupsg2000goo.googlegroups.com... Ok. The host OS time is fine so I'd have no problem using that as the source for my linux guest. What no one has provided yet is an answer to 'how' to get the linux guest VM to get the proper time from the host? How is that NTP's problem? I would have thought the task should be performed by the virtual machine you are using, and you would not need to run NTP on the guest OS. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Flash 400 on all peers; can't get ntpd to be happy
Sorry if the formatting is bad. I don't have a local newsfeed (ISPs seems to have abonded providing that) so I have to post via google. I wraps fine on their editor but I can see where it might not format well in the newsfeed. Ralph, You may be able to use one of the free news services instead, for example: http://www.eternal-september.org/ David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Beginner needs help...
Terje Mathisen terje.mathisen at tmsw.no wrote in message news:54vg48-ttp2@ntp6.tmsw.no... [] A RAIG (Redundant Array of Inexpensive GPSs) setup solves that problem as well. :-) I.e. as I wrote I have 3 Oncores as well. Terje 3 GPS for about US $100 and a little soldering: http://www.sureelectronics.net/goods.php?id=99 Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Flash 400 on all peers; can't get ntpd to be happy
Ralph ra...@depth.net wrote in message news:d695207e-04ec-4664-8580-35bc25806...@glegroupsg2000goo.googlegroups.com... Well it started out as NTP's problem because apparently the clock instability makes it so NTP can't run right on the guest. I understand this isn't so much an NTP problem if the expectation is that NTP can't run on a guest OS, but since everyone seemed to state so matter of factly that the guest should be able get the time from the host, I thought someone here might be able to provide a lead on how that is achieved. I think you need to as the VM vendor about that. Did the VMWare paper help at all? Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Beginner needs help...
Hi all [] Robert Robert, You have had some good advice from other here. I have various Windows systems here running NTP, with offsets of less than 100 microseconds (Windows-7, PC Stamsund, with an attached GPS/PPS device) and less than 1 millisecond (Windows XP, PC Narvik, LAN-synced). Performance: http://www.satsignal.eu/mrtg/daily_ntp.html Configuration: http://www.satsignal.eu/mrtg/daily_ntp.html#Configuration To get this level of offset, I worked closely with Dave Hart who updated the serial support and the interpolation scheme so that it worked better with Windows, and I also use much shorter polling intervals on the LAN than you would use on the Internet. Although there is a FreeBSD system in the network, I would be quite confident about using just a Windows-7 reference clock with a GPS/PPS system (either Garmin GPS 18 LVC, or Sure Electronics evaluation board), with an Internet backup. I hope you may be able to fit such a system within a Windows Domain - I don't use Domains here. GPS 18x LVC: https://buy.garmin.com/shop/shop.do?pID=27594pvID=14555 Sure Electronics board: http://www.sureelectronics.net/goods.php?id=99 Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] still not able to get NTP to sync on windows 7 even w/ more updated binaries
Gautam Thaker ghtha...@gmail.com wrote in message news:bbf7043d-935c-4a9d-8b8e-a30d44779...@8g2000prb.googlegroups.com... On Feb 26, 5:44 am, Dave Hart daveh...@gmail.com wrote: http://davehart.net/moo/ntpd-QPC-20090614-0900.zip That represents the last in a series of 4.2.4p6-based private releases of mine. OK, so started to use this 4.2.4p6 version and immediately saw a reduction in variations in the offset value. see graphic at: http://www.atl.external.lmco.com/projects/QoS/documents/feb26_offset.png I should note a few things: 1) when i switched to this version of ntpd.exe, the ntpq.exe from 4.2.7p98 did not seem to be able to query the daemon. 2) Meingberg Time Service Monitor GUI program was reporting status (presumably since it is based on 4.2.4 ?) 3) I switched to using ntpq.exe from 4.2.4 that comes w/ Meinberg install and that ntpq.exe worked ok. 4) while the offset reported has become much less wild I noted that both 'delay' and 'jitter' values reported are ALWAYS now just 0.977. This should be an indication that something is not right and thus I don't know if i can trust the improved offset value stability. Any comments welcome. Gautam Interesting to compare your: http://www.atl.external.lmco.com/projects/QoS/documents/feb26_offset.png with the earlier: http://www.atl.external.lmco.com/projects/QoS/documents/feb24_1.png It shows just how much better the 4.2.4 version was than the current version. I do hope that this will encourage someone to look again at the code with a view to discovering the differences and making the current version work as well as the previous operation. Even if I had the source code (which I don't), I don't read C well enough, nor do I have the necessary understanding of the core algorithms. Maybe one for that Google Summer of Code, which someone was asking about? (1) is a real pain - why cannot backwards compatibility be provided? Does it make the query program too complex? (4) may just be a function of the lack of interpolation under Vista/Win-7 coupled with the use of a nominal 1000Hz clock (actual interval 0.977ms). As I understand it, that likely means ntp is working as intended on that platform. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] still not able to get NTP to sync on windows 7 even w/ more updated binaries
Are you sure that, on your system, there are no other programs trying to set the time? That is what I thought, that something was jumping the system clock. The fact that the offset value is always anice even value I think proves the clock is not drifting or noisy by being set. -- = Chris Albertson Redondo Beach, California Check that W32time isn't showing in the process list (with Show processes from all users set). I asked what NTP had logged in the event viewer. Also: what is in the drift file (in NTP's etc directory). If it's a number near 500 (either positive or negative) that may indicate that the clock on your PC is rather too far off correct for NTP to be able to correct it (more than 500 parts per million away). Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] still not able to get NTP to sync on windows 7 even w/ more updated binaries
Here is what the Windows7's event log says. The last restart w/ 4.2.7.p98 was started at 3:51. (It is not giving a good sync). Earlier than that I had an error in specifying minpoll=maxpoll=32, but i fixed that and i do see poll value of 32. Level Date and Time Source Event ID Task Category Information 2/24/2011 3:51:02 PM NTP 3 None peers refreshed [] Information 2/24/2011 3:51:02 PM NTP 3 None proto: precision = 999.600 usec Information 2/24/2011 3:51:02 PM NTP 3 None using Windows clock directly Information 2/24/2011 3:51:02 PM NTP 3 None Windows clock precision 1.000 msec, min. slew 6.410 ppm/s Information 2/24/2011 3:51:02 PM NTP 3 None Clock interrupt period 15.600 msec (startup slew -6.4 usec/period) Information 2/24/2011 3:51:02 PM NTP 3 None Performance counter frequency 2.083 MHz Information 2/24/2011 3:51:02 PM NTP 3 None MM timer resolution: 1..100 msec, set to 1 msec [] Thanks, Gautam. The entries look completely normal (compared to a Windows Vista system I have), and in particular, the correct choice of interpolation scheme is being made (I left those entries above). What I am /not/ seeing is any entries by NTP saying that NTP is stepping the time. No, I don't expect Win-7 SP1 to make any difference. I would check again for any power-saving stuff. I would also suggest installing on another Win-7 PC to convince yourself that NTP does work, and to have a base to compare against. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Any experience with Meinberg NTP software on Windows 7?
Once you replace the binaries in C:\Program Files\NTP\bin do you need to do anything extra (such as use Instsrv.exe) to register the new binary. I get a popup saying Erorr 5: access is denied. Any hints welcome. Gautam Gautam, If you are using Vista or Window-7, I advise against installing in the \Program Files\ tree, and using a directory such as C:;\Tools\NTP\ instead: http://www.satsignal.eu/ntp/setup.html The Meinberg installation sets up the NTP service for you. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Any experience with Meinberg NTP software on Windows 7?
http://www.sureelectronics.net/goods.php?id=99 Except there is no indication that this thing puts out a PPS signal. Bill, do you need to add a couple of wires to get an RS-232 level signal, as I describe here: http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm#sure For just over US $30 (and delivered to the UK for a few dollars more) it's not bad, considering that the GPS 18x LVC comes to approaching US $100 over here! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Any experience with Meinberg NTP software on Windows 7?
dwmal...@maths.tcd.ie wrote in message news:201102241413.aa58...@walton.maths.tcd.ie... In comp.protocols.time.ntp you write: Bill, do you need to add a couple of wires to get an RS-232 level signal, as I describe here: http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm#sure For just over US $30 (and delivered to the UK for a few dollars more) it's not bad, considering that the GPS 18x LVC comes to approaching US $100 over here! Cute - I might get one - even my soldering might be up to doing that ;-) David. It's surface mount stuff, David, which I don't normally do, but attaching a couple of leads is OK if you are careful. I happen to have a very narrow bit for my soldering iron, which IIRC is 800F, so hot enough to melt what they call solder these days! But perhaps more modern irons would be OK in any case. As you can tell, it's enamelled copper wire I use, and I would suggest trying to layout and scrape and tin the ends before soldering. Usual anti-static precautions apply. I've ordered a second one as a spare - the unit seems very sensitive, but it would be most interesting to see how it compares with a more expensive box. Do let me know how you get on, and don't worry if the combined postal time is 2-3 weeks! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] still not able to get NTP to sync on windows 7 even w/ more updated binaries
Based on 1 response I upgraded to ntp-4.2.7p98-win-x86-bin.zip from http://davehart.net/ntp/win/x86/ However, though NTP is running and the offset values on my win7-32 box are quite horrible. (i should note that on same subnet using same time server a fedora12 box achieves sub 1msec offset easily and stays there. ) The graphic below shows how terrible the ntp is behaving on my windows 7 box. http://www.atl.external.lmco.com/projects/QoS/documents/win7_feb23.png What else can I try here? This is puzzling. Is there any option/patch one has to apply to windows7-32 for NTP to work well on it? Gautam On my LAN, I set minpoll=maxpoll=5 (32 seconds), and this is what I see on a LAN-synched Win-7 64-bit PC: http://www.satsignal.eu/mrtg/alta-ntp-b.html One parameter which affected other very network sensitive software was: http://en.wikipedia.org/wiki/Multimedia_Class_Scheduler_Service http://support.microsoft.com/kb/948066 http://msdn.microsoft.com/en-us/library/ms684247%28VS.85%29 In: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile\ I set: NetworkThrottlingIndex to -1 () (stops throttle) and SystemResponsiveness to 80 (=80% to non-multmedia) these may make a difference for you, although I didn't change them to get better timekeeping. Feed the box with PPS and you might see: http://www.satsignal.eu/mrtg/stamsund_ntp_2.html which is from a Windows-7 32-bit system. Are you sure that, on your system, there are no other programs trying to set the time? What do the NTP entries in the event viewer say? Have you set the High performance power option on your PC, or at least stopped anything which grossly changes the CPU clock frequency? I would like to see your systems as good as mine, if I can help! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Any experience with Meinberg NTP software on Windows 7?
Hi: I have had excellent results using http://www.meinberg.de/download/ntp/windows/ntp-4.2@lennon-o-lpv-win32-setup.exe on a windows XP platform, but on windows 7 I never get a good sync. (The NTP server is a high quality statum 2 time server which provides excellent time to Fedora/Linux clients.) I was wondering if anyone has any experience w/ windows 7 with Meinberg (or any other NTP) software. Gautam Gautam, I have also found that Windows Vista and Windows-7 are not such good time keepers as Windows XP. Windows-7 32-bit will work as a stratum-1 server with a GPS/PPS serial reference: http://www.satsignal.eu/mrtg/stamsund_ntp_2.html being typically within 50 microseconds, and I have other systems, including a Windows-7 64-bit system synced over the LAN: http://www.satsignal.eu/mrtg/alta-ntp-b.html which is within a couple of milliseconds (using 32s poll, minpoll=maxpoll=5). The problem is that the rather excellent interpolation scheme developed for Windows cannot be used with the later versions from Vista onwards which have a higher clock interrupt rate. You can see the performance of all my systems here: http://www.satsignal.eu/mrtg/performance_ntp.php If timekeeping on Windows is critical, consider getting a PPS signal sent round to the PCs which matter. You need pay no more that US $35 for a PPS source: http://www.sureelectronics.net/goods.php?id=99 Be aware that later versions of NTP are available. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] GPX18x LVC 3.50 firmware - high serial delay problem workround
http://www.sureelectronics.net/goods.php?id=99 Thanks for the link! Even though I already have a big bunch of GPSs, I've placed an order for one of those kits. :-) I really liked the multiple interfaces, the ms precision for the NMEA timestamp and the total price which is below the minimum import duty floor here in Norway. :-) Terje I'm really looking forward to your expert comments on this board! Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] GPX18x LVC 3.50 firmware - high serial delay problem workround
Ok I'll go back over your past posts re the problem and report it myself to Garmin UK and see what they say - once I get something back I'll let you know. I have 3.60 running anyway with no new problems (that I can see) Thanks, Q, I can't see it doing any harm. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] ANN: Interruption to UK MSF 60 kHz signal
Folks, I have received the following announcement: __ Notice of Interruption to MSF 60 kHz Time and Frequency Signal The MSF 60 kHz time and frequency signal broadcast from Anthorn Radio Station will be shut down over the period: 10 March 2011 - from 10:00 UTC until 14:00 UTC The interruption to the transmission is required to allow maintenance work to be carried out in safety. __ Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] Odd results with Oncore UT+ ref clock
I suspect now the PPS is failing somehow. I can see the serial data appear in the log every second. But mixed in there is a error message that reads ONCORE[0]: ONCORE: oncore_get_timestamp, error serial pps. I'll likey grep the code for the error string and see what it's doing. I just bught an HP universal counter and when UPS delivers it I'll have the abilty to measure the PPS at sub uS level. I could have a plumbing pproblem as the UT+ is 3rd floor and the computer is 1st floor with 75 feet of RS232 over cat-5 between. [] Chris Albertson Redondo Beach, California Could it be that the GPS is occasionally losing lock and stopping the PPS - e.g. too few satellites in view? Can you check its reported status from your logs? Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] ntp-4.2.6p3-1.el5 - minpoll local PPS source
Q ..@.. wrote in message news:4d45b7cb$0$2534$da0fe...@news.zen.co.uk... Having looked through some ntp doc's and lots of websites I'm a bit confused as to what I 'should' do. My local PPS source is set for 'minpoll 4' (16 sec) this has had the knock on effect that the other network based servers have all decided to poll at 64sec intervals. Most of the web sites I've read say I should leave the 'minpoll 4' statement for the PPS source, but the ntp docs talk about a bug being fixed with the SHM driver and that you need not set 'minpoll 4' for local PPS sources. Could anyone please let me know what I 'should' do. You could try lines such as: server 0.uk.pool.ntp.org iburst minpoll 10 server 1.uk.pool.ntp.org iburst minpoll 10 for the Internet servers. Cheers, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] DCF77 support in the Windows NTP port?
Folks, Is there simple DCF77 support in the Windows NTP port? This would be for the simple receiver described here: http://www.rrs-web.net/in3her/dcf77_32.html A friend has one of these devices and is interested in syncing multiple PCs. I only see manufacturer-specific drivers (types 38, 39 and 44) and I'm unsure whether the hardware above is similar to one of these types, and whether those types are in the Windows build (or how to find that out for myself). Perhaps type 44 is the closest and is fairly generic for a serial-line presentation of the DCF77 data? Thanks, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
