Fellow techs,

Thanks for tuning into my issue of the day. I need to achieve 2 things.
The first is to obtain and install the PPS kit onto Spectracom's
TTS240rb. I spoke with the support folks a Spectracom and they
suggested I post here. The second is to install the PPS kernel
components on a RedHat ES 4 system running 2.6.9-XX.

I've managed to download and compile the nanokernel package from Mr.
David Mills' site, but getting the (working) hooks into my distro have
eluded me. The test program that was provided in the package ran
without incident (if that helps).

Thanks in advance any and all help,
Allen

abrown@mlp.com writes:

> Fellow techs,
> 
> Thanks for tuning into my issue of the day. I need to achieve 2 things.
> The first is to obtain and install the PPS kit onto Spectracom's
> TTS240rb. I spoke with the support folks a Spectracom and they
> suggested I post here. The second is to install the PPS kernel
> components on a RedHat ES 4 system running 2.6.9-XX.
> 
> I've managed to download and compile the nanokernel package from Mr.
> David Mills' site, but getting the (working) hooks into my distro have
> eluded me. The test program that was provided in the package ran
> without incident (if that helps).

So you are basically looking for someone that writes code for you? There is no
released PPSkit for Linux kernel 2.6, and definitely not for any Enterprise
Server release. Dave Mills' nanokernel is a "simulator" AFAIK/R. So what do
you expect by running it?

Regards,
Ulrich

> 
> Thanks in advance any and all help,
> Allen

Ulrich Windl wrote:
> abrown@mlp.com writes:
>
> > Fellow techs,
> >
> > Thanks for tuning into my issue of the day. I need to achieve 2 things.
> > The first is to obtain and install the PPS kit onto Spectracom's
> > TTS240rb. I spoke with the support folks a Spectracom and they
> > suggested I post here. The second is to install the PPS kernel
> > components on a RedHat ES 4 system running 2.6.9-XX.
> >
> > I've managed to download and compile the nanokernel package from Mr.
> > David Mills' site, but getting the (working) hooks into my distro have
> > eluded me. The test program that was provided in the package ran
> > without incident (if that helps).
>
> So you are basically looking for someone that writes code for you? There is no
> released PPSkit for Linux kernel 2.6, and definitely not for any Enterprise
> Server release. Dave Mills' nanokernel is a "simulator" AFAIK/R. So what do
> you expect by running it?
>
> Regards,
> Ulrich
>
> >
> > Thanks in advance any and all help,
> > Allen

I was hoping the code was already written. My ultimate goal is to get
my clocks within 1ms.I've recently managed to get nearly all systems
consistenly within 5-20ms. In the introduction of "Generic Nanosecond
Kernel Timekeeping", they state that "...the primary purpose of these
modifications is to improve timekeeping accuracy to the order less than
a millisecond and, ultimately, to a nanosecond ...". In downloading the
code I wasn't entire sure what it included.

Regardless, after running the test scripts, it appeared that my kernel
and hardware could  in fact get to within a millisecond. My next
question was, how do I get that improvement into my environment. The
answer from my vendor was 2 part: 1. get a PPS kit for my Spectracom
time server and 2. get the appropriate PPS implementation for my client
systems. In looking around the internet, I've found a few postings that
led me to believe that people have this working for other linux
implementations that were NTPv4 and various kernel revs.

Is this making sense? Thanks for your time.

Allen

abrown@mlp.com wrote:
> Ulrich Windl wrote:
> 
>>abrown@mlp.com writes:
>>
>>
>>>Fellow techs,
>>>
>>>Thanks for tuning into my issue of the day. I need to achieve 2 things.
>>>The first is to obtain and install the PPS kit onto Spectracom's
>>>TTS240rb. I spoke with the support folks a Spectracom and they
>>>suggested I post here. The second is to install the PPS kernel
>>>components on a RedHat ES 4 system running 2.6.9-XX.
>>>
<snip>
> Regardless, after running the test scripts, it appeared that my kernel
> and hardware could  in fact get to within a millisecond. My next
> question was, how do I get that improvement into my environment. The
> answer from my vendor was 2 part: 1. get a PPS kit for my Spectracom
> time server 

  I think you may have misunderstood your vendor. I had a look at the
Spectracom data sheet and your device is a complete ntp server with the
extra PPS + other time code output. You do not need, and could not apply 
any modifications to the propriety Server code in the box.

  As for a PPS Kit for your linux distrib, I suggest you talk to
Redhat. They may have an implementation ready to go, else you could 
tailor  PPSkit-light yourself.
http://www.kernel.org/pub/linux/daemons/ntp/pps/

   from Spectracoms data sheet:


OUTPUTS:
  Type                           Connector
  Ethernet 10/100 BaseT          RJ45 (auto sensing)
  Two RS-232 Serial Comm         DB9 female
  Two RS-485 Once-per-second     3.81mm Terminal Block
  IRIG B/E AM/TTL                BNC
  1PPS, Pulse-per-second         BNC

  so you will need hardware to convert PPS (or IRIG ) to rs232 input to 
your server. THese outputs usually put out low voltage signals not
suitable for direct connect to PC interfaces.

  10 MHz                         BNC
  Three Alarm/Programmable Timer 3.81mm Terminal Block

   So using just the NTP server over ethernet  you should be seeing sub 
millisecond accuracy. To get better you should check try the Type 4 
refclock driver which states it supports all known Spectracom servers
over the rs232 interface, where I guess there is proprierty time code
though I could not down load the manual to check what formats are available.

   I could not see a generic IRIG driver available. There must be one
somewhere.

and 2. get the appropriate PPS implementation for my client
> systems. In looking around the internet, I've found a few postings that
> led me to believe that people have this working for other linux
> implementations that were NTPv4 and various kernel revs.
> 
> Is this making sense? Thanks for your time.
> 
> Allen
> 

Mike,

Thanks for the details. This was right on the money. I had another chat
with the vendor and after several iterations of possible configurations
he provided the " ... you can upgrade to this new model (the 9238) that
has all of the functionality you need under the cover, PLUS it uses
ntpv4 compliant code."

I'll be sure to tap RedHat about the PPS kit for ES4, but they're
typical answer for such requests is wait for  the next release. I'll
see what I can do with PPSkit lite if that is the case.

Once again, thanks to all that were invloved.

Allen

mike wrote:
> abrown@mlp.com wrote:
> > Ulrich Windl wrote:
> >
> >>abrown@mlp.com writes:
> >>
> >>
> >>>Fellow techs,
> >>>
> >>>Thanks for tuning into my issue of the day. I need to achieve 2 things.
> >>>The first is to obtain and install the PPS kit onto Spectracom's
> >>>TTS240rb. I spoke with the support folks a Spectracom and they
> >>>suggested I post here. The second is to install the PPS kernel
> >>>components on a RedHat ES 4 system running 2.6.9-XX.
> >>>
> <snip>
> > Regardless, after running the test scripts, it appeared that my kernel
> > and hardware could  in fact get to within a millisecond. My next
> > question was, how do I get that improvement into my environment. The
> > answer from my vendor was 2 part: 1. get a PPS kit for my Spectracom
> > time server
>
>   I think you may have misunderstood your vendor. I had a look at the
> Spectracom data sheet and your device is a complete ntp server with the
> extra PPS + other time code output. You do not need, and could not apply
> any modifications to the propriety Server code in the box.
>
>   As for a PPS Kit for your linux distrib, I suggest you talk to
> Redhat. They may have an implementation ready to go, else you could
> tailor  PPSkit-light yourself.
> http://www.kernel.org/pub/linux/daemons/ntp/pps/
>
>    from Spectracoms data sheet:
>
>
> OUTPUTS:
>   Type                           Connector
>   Ethernet 10/100 BaseT          RJ45 (auto sensing)
>   Two RS-232 Serial Comm         DB9 female
>   Two RS-485 Once-per-second     3.81mm Terminal Block
>   IRIG B/E AM/TTL                BNC
>   1PPS, Pulse-per-second         BNC
>
>   so you will need hardware to convert PPS (or IRIG ) to rs232 input to
> your server. THese outputs usually put out low voltage signals not
> suitable for direct connect to PC interfaces.
>
>   10 MHz                         BNC
>   Three Alarm/Programmable Timer 3.81mm Terminal Block
>
>    So using just the NTP server over ethernet  you should be seeing sub
> millisecond accuracy. To get better you should check try the Type 4
> refclock driver which states it supports all known Spectracom servers
> over the rs232 interface, where I guess there is proprierty time code
> though I could not down load the manual to check what formats are available.
>
>    I could not see a generic IRIG driver available. There must be one
> somewhere.
>
> and 2. get the appropriate PPS implementation for my client
> > systems. In looking around the internet, I've found a few postings that
> > led me to believe that people have this working for other linux
> > implementations that were NTPv4 and various kernel revs.
> > 
> > Is this making sense? Thanks for your time.
> > 
> > Allen
> >

abrown@mlp.com wrote:

> I'll be sure to tap RedHat about the PPS kit for ES4, but they're
> typical answer for such requests is wait for  the next release. I'll
> see what I can do with PPSkit lite if that is the case.

You do not need PPS support in the kernel to use a PPS output on Linux.
Linux has TIOCMIWAIT in the kernel by default. While it's not as good
as kernel support for a PPS output, it's more than good enough for most
applications.

http://beta.webmaster.com/~jk/shm_linux_clock.c

DS