Re: [time-nuts] English To German Email Translation for free
Hi, On Mon, May 19, 2014 at 1:16 AM, Bob Burchett wrote: > I have a friend who speaks fluent German; send me an email of what you want > to say BUT you should know that when I need any language of text I use this > website: http://www.freetranslation.com/en/translate-english-german > > They do most any language but this one is for English to German. I can help translate from or to German, as I lived in Germany for a large portion of my life (and in recent times). If you want a good syntax checker, go to http://www.duden.de. Good luck! ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] The Problem with Time & Timezones - Computerphile
On 9 May 2014 21:01, "Hal Murray" wrote: > > > hol...@hotmail.com said: > > Ahh, but with Lady Heather you can specify the time zone offset (down to > > the second) and the when the daylight savings time switchovers occur. And > > from experience, I can tell you that the code to do it is a royal pain in > > the ass... not all that hard to do, but a pain to test. > > Part of the problem is that "when the daylight savings time switchovers > occur" changes over time. The problem is a whole lot easier if all you are > interested in is converting the current UTC to the current local time. > > The *nix world uses the time-zone database. I assume it is available on > Windows too. > https://en.wikipedia.org/wiki/Tz_database That is the Olson Timezone Database, aka tzdata. I wrote a compiler for it once, the format is very fun to parse and there are some great things to be learned. Specifically figuring all edge cases was a fun exercise. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 5370 processor boards available
Hi Brian, it's less about caching pending writes to file handles that are waiting inside the system. That's most likely to work well within a short period of time. The issue is if you're using the system to its full extent. Among others you'd like to write applications for the BBB that enhance the 5370's capabilities. You don't want to bother with hard real time, compilation, memory layout, etc, all of them problems each of which will make your development time 10x longer and your fun time 20x shorter. So instead you use something like Python or Java. Then, you also don't really bother to ensure that your program can be interrupted at any time, since that's another level of complexity. Coroutines? Continuation passing style? Reactive programming? Why bother? Then you make a few other decisions that make your program easier to make and more difficult to shut down immediately in a clean manner. So let's say it's running and it is collecting data which is crucial to you. Maybe you again didn't bother to make sure that if the program crashes it will not corrupt its data. So now your BBB gets the power loss interrupt, sends kill -15 to all processes and most of them exit. Your program doesn't so likely Linux tries to send signals 2, then 1, then 9 at which point your program will certainly crash (sig 9 means "crash now"). So your program will likely eat all the data. Note that all of the shortcuts I mentioned above are fairly reasonable defaults that save days of work per project for no improvement in reliability, since, after all, a suitable battery only costs $5. Cheers, D. On Thu, Feb 27, 2014 at 7:47 PM, Brian Lloyd wrote: > It is interesting to watch this thread. The most interesting thing is the > fact that no one has asked or answered the basic question: is there a > problem? There are a lot of solutions for what may be a complete non-issue. > > Given that Linux and BSD are reliable and stable on standard PC platforms > connected to mains power without a UPS, that suggests to me that there is > likely no issue. Sure, back in the bad ol' days you had to sync;sync;sync > the filesystem prior to shutdown and then, if there had been a power fail, > fsck it on power up. But those days have been gone for a LONG time. > > The modern filesystems reduce the exposure to the possibility of file > system corruption to a tiny probability, and then the system further > reduces that by providing a power-fail detection system that allows the > critical pending writes to be flushed prior to final power-fail, thus > leaving the FS in a completely deterministic state. > > I suppose that on the night of a full moon when the lightning flashes and > the dog barks, conditions might be right to corrupt the file system, but > then, that could happen when the battery goes dead or catches fire too. ;-) > > It seems to me that the bard put it pretty well, "... much ado about > nothing." > > -- > Brian Lloyd, WB6RQN/J79BPL > 706 Flightline Drive > Spring Branch, TX 78070 > br...@lloyd.com > +1.916.877.5067 > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 5370 processor boards available
On Thu, Feb 27, 2014 at 6:22 PM, Scott Newell wrote: > At 11:03 AM 2/27/2014, Poul-Henning Kamp wrote: > >> Seriously: Keeping the computer alive and eating power is >> silly. We just need to find out how to get the Linux configured >> correctly. > > > Exactly. We use the PC-Engines ALIX x86 single board computer stuff at work, > and even I didn't have too much trouble getting a pretty much stock Debian > installation 'adjusted' to run with the CF card mounted as read-only. I've > yet to see a problem with power cycles. (But I've only done the power cycle > bench test a few hundred loops.) > > -- > newell N5TNL My assumption is that, unlike an embedded computer which is plug-and-forget, this thing will get modified, developed on, played around with, etc, all of which includes userland software (= possibly long shutdown times) and disk access (= possibly long shutdown times). It's trivial to run a read-only system but that's limiting and takes out the fun of tinkering with the BBB to make your own applications and other stuff. You might say that we could run the stock system RO and add any user-supplied stuff to RW media and just say that it isn't going to survive a power-down. But that's not really a comfortable situation. D. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 5370 processor boards available
On Thu, Feb 27, 2014 at 6:03 PM, Poul-Henning Kamp wrote: > In message > > , "cheater00 ." writes: > >>If having a battery in the device makes some of you queasy, you could >>always put it outside, on the back. But I seriously believe there are ways >>to make battery backup which will not leak. > > Seriously: Keeping the computer alive and eating power is > silly. We just need to find out how to get the Linux configured > correctly. > > (Or port it all to FreeBSD, which I'm considering, because there > I know how to do it :-) Oh, of course it's not about keeping the computer on at all times, it's about having a contingency for the 0.1% case when your computer does not shut down in the assumed time. Unless you develop your system and everything running in it as hard real time, you cannot escape the fact that sometimes the thing will take longer than expected to shut down. And at some point that will cause data loss. A suitable battery costs $5. Is your time worth so much less than $5 that you actually consider the task of building your own Linux distribution for this case, or even just finding one that will work relatively problem-free? D. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 5370 processor boards available
If having a battery in the device makes some of you queasy, you could always put it outside, on the back. But I seriously believe there are ways to make battery backup which will not leak. D. On 27 Feb 2014 06:52, "Chuck Harris" wrote: > That fix presumes that the power line never quits at > inappropriate times. This winter has provided me with > ample reminders that power can go out anytime. > > I think a better solution would be to find a very large > "super cap" and power the BBB from that while giving it > a power fail interrupt to quickly sync the file system. > > -Chuck Harris > > John Seamons wrote: > >> On Feb 25, 2014, at 12:59 PM, John Seamons wrote: >> >> I may have a solution for the power-off problem that doesn't involve >>> batteries >>> or supercaps. It has the added advantage of providing instant-on. >>> >> >> From the latest documentation: >>> >> >> "One solution to the annoyance of having to halt the BBB before the >> instrument is >> powered off is simply to keep the BBB running by providing it a secondary >> source >> of power via the USB-mini port. The BBB already understands how to select >> between >> two sources of power: the USB-mini and +5V barrel connectors (the latter >> of which >> is actually being delivered from the 5370 via the board expansion >> connectors). The >> app detects when the instrument has powered down and resumes running when >> power is >> restored. USB power could come from an external USB hub or charger. You >> may have >> to obtain a longer USB cable than the one supplied. Be certain to only >> use the >> USB-mini connector that is adjacent to the Ethernet RJ45 connector. Do >> not use the >> USB-A connector on the other end of the board as that port will not >> accept input >> power. >> >> Some of you might even figure out how to derive +5V for the USB-mini >> cable from >> the 5370 oven power supply card that is always powered if the instrument >> is off >> but the line cord is plugged in. But beware of the potential problem of >> conducting >> noise from the BBB to the reference oscillator over such a connection. >> Some >> experimentation and measurement is necessary. The planned USB/Ethernet >> connector >> card that replaces the current HPIB one at the back-panel could host a >> voltage >> regulator. Aligator clip connections to the '+25V UNREG' and GND test >> points on >> the oven power supply would alleviate the need for any soldering." >> >> ___ time-nuts mailing list -- >> time-nuts@febo.com To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the >> instructions there. >> >> ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 5370 processor boards available
You can fit linux with a comfortable amount of stuff in 20 MB, but you want more than that for more advanced programs. You should not use the built in ssd for writing. It has limited writes and cannot be replaced. Use a card. You can tailor linux so that it has minimal services but the question of how to make it shut down in a predictable amount of time is a complex issue and you are best off finding an existing project that focuses on this. So rather than limit yourself to an esoteric set of requirements I recommend using a battery that'll run the BBB for 15 minutes and will charge in an hour while it's on. My day job is among others as a linux admin. D. On 27 Feb 2014 15:47, "Didier Juges" wrote: > The BBB has 2GB of flash on board (non removable) and has a micro SD > socket. Would not be too hard to keep a backup copy of the OS and apps on > the SD card so that it would be easy to boot from SD and reload the > built-in flash if the BBB fails to boot from the built-in image. > > That would not be a replacement for a workable, safe boot process that can > be interrupted without trashing the file system. Just a few days ago, an > overnight storm caused power to flicker maybe 5 times in less than a > minute. My Raspberry Pi managed to survive it, but I am not sure that will > always be the case. > > I think a super cap with proper shutdown routine would probably the > easiest to implement. Alternately, running the flash read only, copy OS, > apps and everything else to a RAM disk and run from the RAM disk would > probably be the safest. Not sure you can do that with 512MB of RAM without > some serious pruning of the Linux kernel. > > Didier KO4BB > > > On February 27, 2014 2:26:13 AM CST, Hal Murray > wrote: > > > >> I think a better solution would be to find a very large "super cap" > >and > >> power the BBB from that while giving it a power fail interrupt to > >quickly > >> sync the file system. > > > >The advantage of something like the BBB is that it runs Linux so you > >have a > >nice environment in which to run your code. The disadvantage of Linux > >is > >that it's complicated and you have things like file systems that can > >get > >trashed. Now, in addition of being the sysadmin for your PC(s), you > >have to > >be an admin for your lab gear. That may be more "interesting" that you > >were > >expecting. A friend reports that his scope caught a virus... > > > >The Linux ext4 file system is pretty robust. There are lots of PCs out > >there > >that mostly survive power failures. > > > >If I was worried about the file system getting trashed on power off, > >I'd work > >on the software long before I added a super-cap. I think my first try > >would > >be to run the file system read-only until I figured out that I needed > >to > >write a file. Then I would know something about how much data I wanted > >to > >write and the usage patterns. > > > >You can help a lot with flush() in the right places in your code. That > >may > >cost performance if you are writing a lot of data. > > > > > > > >Another approach is to make sure you can put the "disk" back together > >easily > >and quickly. Then it's not such a big deal if/when the disk gets > >trashed. > >That's probably a good idea anyway. Power fail isn't the only thing > >that can > >trash a disk. > > > >It shouldn't take much more than a simple script to format the disk and > >copy > >over all the bits from a backup place on a PC. Maybe it's install the > >standard distro package and then add your bits. (That's assuming you > >can > >take the disk out of the BBB and plug it into a PC.) > > > > > > > > > > > > > > > >-- > >These are my opinions. I hate spam. > > > > > > > >___ > >time-nuts mailing list -- time-nuts@febo.com > >To unsubscribe, go to > >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >and follow the instructions there. > > -- > Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other > things. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thermal Compensation: Digital vs Analog
Hi Bob, better use an FIR. Your rolling average didn't smooth out enough because it doesn't have a cutoff low enough. Hysteresis is not going to help here that I know of. Cheers, D. On Wed, Feb 26, 2014 at 6:05 PM, Bob Stewart wrote: > Hi Atilla, > > The GPSDO is VE2ZAZ's circuit with new code. It detects phase crossings to > change the DAC, so it has a phase crossing for every update. I'm working on > a TIC design but haven't started on the hardware. In the interim, I hooked > up an LM34 thermistor and have been playing with that. In the 8 hour plot > below, there are no frequency updates, only temperature updates. I've tried > a rolling average, but it doesn't smooth it enough, so I'll have to try > hysteresis next. The orange/green/blue line is the DAC. The red line is the > thermistor. The cyan smear is the phase plot of 1PPS from my Adafruit > (MT3339) against the OCXO (Trimble 34310-T). The units on the right > correspond to the temperature - 100 degrees at the EFC divider directly > beneath the OCXO. Also, they correspond to the wrapped phase, where 0-20 is > 0-360 degrees. The OCXO is limited to a swing of about +/- 1.1Hz at the > moment. > > http://www.evoria.net/AE6RV/TempComp/GPSDO.png > > In the plot below is the ADEV. Hopefully it's self explanatory. The phase > has varied a bit more than 180 degrees during the test. > > > http://www.evoria.net/AE6RV/TempComp/ADEV.png > > The biggest influence on temperature seems to be the low quality divider > resistors in the EFC divider chain. I have new low TempCo resistors but I > couldn't resist playing with these first. Without temperature compensation, > phase would vary through about one cycle every change to the red (thermistor) > line. > > > Bob - AE6RV > > > > >> >> From: Attila Kinali >>To: Bob Stewart ; Discussion of precise time and frequency >>measurement >>Sent: Wednesday, February 26, 2014 10:23 AM >>Subject: Re: [time-nuts] Thermal Compensation: Digital vs Analog >> >> >>On Wed, 26 Feb 2014 08:09:44 -0800 (PST) >>Bob Stewart wrote: >> >>> I've been experimenting with digital thermal compensation on my GPSDO. >>> The results have been favorable for a 14 bit dithered PWM-based DAC, but >>> leaves a bit to be desired in the big picture. And it takes up a lot of >>> program bytes on my PIC.. What's the general consensus on this? Should >>> thermal compensation be completely analog? >> >>Out of pure interest. Could you elaborate what results you got? >>Ie. what does your GPSDO look like? How do you compensate for the >>temperature coefficient? How much did that improve performance >>compared to non-compensated operation? Did you try any other approaches? >>Why? Why not? >> >>Yes, i'm a curious mind :-) >> >>Thanks in advance >> >>Attila Kinali >> >>-- >>The trouble with you, Shev, is you don't say anything until you've saved >>up a whole truckload of damned heavy brick arguments and then you dump >>them all out and never look at the bleeding body mangled beneath the heap >>-- Tirin, The Dispossessed, U. Le Guin >> >> >> > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 5370 processor boards available
Thanks for the info. It could still be power off... just add a large capacitor as voltage backup and make the unit sense when power is off. It should be able to shut down quickly enough. That's how it works most of the time. Alternatively add some 1.5v batteries and a charger. That should never run out. Running a PC without backup power is asking for trouble. A few 1.5v batteries and a charger and buck-boost cost only 10 bucks. D. On 24 Feb 2014 18:57, "paul swed" wrote: > D > I can give you some insights here. Others will be more effective. We all > agree that the 5370 frequency counters are great devices from 1980. Right > there is the first issue. The old micros are getting old and failing. I > have lost both 6800s and eproms. > Thank heavens stuff is still available. > But this board replaces those items completely. Welcome to 2014. Now we > just have to worry about big fat capacitors. > > In addition it gives you remote control other then GPIB. We all love GPIB, > but us lazy types like Ethernet better. Cables are easier to manage. > > Finally the crazy thing is it gives you web services. Wow for a 1980s box. > All while leaving the front panel operation intact for simple quick > applications. > > The only thing that can be annoying is there is a shut down procedure for > the unit now. It used to be power off. > > All of the above for $90. > Hope that helps you. > Regards > Paul > WB8TSL > > > > > > > > > On Mon, Feb 24, 2014 at 12:16 PM, Pete Lancashire > wrote: > > > Goto one of the places selling the BB Black and look up BB View. > > > > Not pushing this disty just one that has a decent image > > > > > > > http://www.element14.com/community/docs/DOC-55844/l/element14-bb-view-lcd-cape-for-beaglebone-family-boards > > > > > > > > > > > > On Mon, Feb 24, 2014 at 1:50 AM, cheater00 . > wrote: > > > > > Hi, > > > I browsed the page and the GitHub repository for a while, and read the > > > readme and read-more documents, but I still don't know what it > > > actually adds. > > > > > > Perhaps it would be a good idea to document this? > > > > > > Cheers, > > > D. > > > > > > On Mon, Feb 24, 2014 at 9:38 AM, Poul-Henning Kamp > > > > wrote: > > > > In message <45dfb8f9-3595-4a5d-8dcc-fd7317988...@jks.com>, John > > Seamons > > > writes: > > > > > > > >>I am now accepting general orders for the hp 5370 processor > replacement > > > board. > > > >>More info and ordering information at: > > > > > > > > As one of the Beta-testers I can highly recommend this, it really > gives > > > > your HP5370 a kick into the next millenium. > > > > > > > > The potential for future improvements is also virtually unlimited: > > > > > > > > How about hooking up an LCD display and calculate and show allan > > > > variance in real time ? > > > > > > > > Thanks a LOT John! > > > > > > > > -- > > > > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > > > > p...@freebsd.org | TCP/IP since RFC 956 > > > > FreeBSD committer | BSD since 4.3-tahoe > > > > Never attribute to malice what can adequately be explained by > > > incompetence. > > > > ___ > > > > time-nuts mailing list -- time-nuts@febo.com > > > > To unsubscribe, go to > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > and follow the instructions there. > > > ___ > > > time-nuts mailing list -- time-nuts@febo.com > > > To unsubscribe, go to > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 5370 processor boards available
Hi, I browsed the page and the GitHub repository for a while, and read the readme and read-more documents, but I still don't know what it actually adds. Perhaps it would be a good idea to document this? Cheers, D. On Mon, Feb 24, 2014 at 9:38 AM, Poul-Henning Kamp wrote: > In message <45dfb8f9-3595-4a5d-8dcc-fd7317988...@jks.com>, John Seamons > writes: > >>I am now accepting general orders for the hp 5370 processor replacement board. >>More info and ordering information at: > > As one of the Beta-testers I can highly recommend this, it really gives > your HP5370 a kick into the next millenium. > > The potential for future improvements is also virtually unlimited: > > How about hooking up an LCD display and calculate and show allan > variance in real time ? > > Thanks a LOT John! > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Measuring 1 PPS with an HP 5335A
Maybe it needs more pulse width at low freq? D. On 16 Feb 2014 20:15, "Jimmy Burrell" wrote: > I've recently purchased an HP 5335A and for the most part, we're getting > along famously. Then I tried to measure my GPS' 1 PPS pulse. I'm not seeing > anything Iike what I'd expect to see, e.g. 0.01. Doesn't matter what > type of measurement I select (freq, period) the measurements are nowhere > near "1". In fact they are all over the place and changing a lot faster > than once per second. > > My first thought was "not enough signal" present at the input of the > counter causing a low SNR. But my scope says it's better than 2v on p-p. > According to the HP5335A manual, that should make the counter happy. > > I've never tried measuring any freq. this slow so I'm out of my element. > Probably missing something obvious. > > Any of this ringing a bell with anyone? Any clues or suggestions? > > Many thanks, > > Jimmy... > N5SSPE > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Resistors in VCO
You can improve most old VCOs by removing voltage references derived from voltage rails and replacing them with REF0x chips. D. On Fri, Feb 14, 2014 at 6:35 PM, Tom Knox wrote: > Hi everyone, some VC oscillators I have played with keep trimmer resistor in > circuit to adjust the EFC close enough for the PLL to work. I was wondering > if changing to more stable resistors could improve ADEV and P/N performance. > Also could this add stability if used to divide the loop voltage. It seems > foil resistors are exceptional in many ways. Do most high end oscillators > already use foil? > On a unrelated but far more important thought, Make sure you remember to do > something nice for that special women or man in your life today. The life you > save may be your own. > > Thomas Knox > > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
