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[time-freq] Linux PPS and FreeBSD issues

Gregg Levine gregg.drwho8 at gmail.com
Sat Dec 29 02:36:47 UTC 2007

On Dec 28, 2007 2:27 PM, Jeff Mock <jeff at mock.com> wrote:
> John described the situation precisely.  It's been a sad state of
> affairs for many years.  I did a contract project several years ago that
> needed good PPS timing source to solve a problem serving long running
> MPEG-2 streams.  I wound up paying to get PPSkit updated to PPSkit-2.1.2
> in hopes of making the code part of the official kernel releases.
> We solved our immediate PPS problem, but never got anyone interested in
> making the PPSkit code part of the regular kernel release. It doesn't
> seem to be a technical issue, there really is some bad chemistry going
> on with PPS support and the kernel people.
> jeff
> John Ackermann N8UR wrote:
> > Hi Gregg --
> >
> > I'm by inclination a Linux guy, but unfortunately there is some sort of
> > bad juju between the kernel people and the NTP people, and as a result
> > getting decent PPS timekeeping out of Linux is an ongoing challenge.  I
> > run FreeBSD (actually, the CF-based nanoBSD version) on my Soekris
> > servers as that seems to be the best way to make things work.
> >
> > There is a shared memory (shm) program called shmpps that can pick up a
> > PPS signal from a serial port and pipe it to NTP, but I've had trouble
> > keeping that going for long uptimes.
> >
> > It's a shame that Linux seems, for reasons I don't understand, to be
> > unable/unwilling to have the necessary kernel stuff to avoid patches,
> > but it's been that way for years and I haven't seen any sign of changes...
> >
> > John
> > ----
> >
> > Gregg Levine said the following on 12/27/2007 06:43 PM:
> >> Hello!
> >> I've been sorting through and reading messages on news://comp.protocols.ntp .
> >>
> >> It seems to be an interesting study. There is a group there (or it
> >> seems to me to be one.) that prefers FreeBSD exclusively. And there
> >> are people like myself who are concerned with the PPS inclusion into
> >> the Linux kernel. Accordingly there are kits available for this on the
> >> Kernel.org server. But only for and for The author
> >> of the kit is interested in updating this, but he's not clear on when
> >> it would be released for the later 2.6 ones.
> >>
> >> There is even one fellow who has NTP running on his Sun box from the
> >> same time period as the I486DX2, he's got it running rather nicely.
> >> But the big question for me is simply running Linux on hardware from
> >> the same time period, and naturally that's what I've been up to.
> >>
> >> The last I time I investigated FreeBSD was during the ramp up to
> >> version 4.0. I daresay I never got things to work properly then. I've
> >> heard some interesting complaints about building a kernel for that
> >> operating system, versus the others from the BSD family, and Linux.
> >>
> >> Would anyone care to comment?
> >
> >
> > _______________________________________________
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> >
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I agree. It seems that the fellow I chose for these antics was a
system I knew very well. The problem is that the computer insists he's

And runs my distribution with kernel releases of Linux Kernel 2.2.16
and 2.2.18 very well.

He's got issues with newer ones because he's a memory challenged I486
rather then any of the faster Pentium types.

I'll know more as my activities progress. I'll probably end up
ordering the Soekris boards that are described on the PHK website RSN.
Gregg C Levine gregg.drwho8 at gmail.com
"This signature was once found posting rude
 messages in English in the Moscow subway."

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