[ntp:questions] ntp server specs

David Woolley david at ex.djwhome.demon.invalid
Mon Jun 13 07:03:10 UTC 2011

chipper wrote:
> If I wanted to feed a group of linux machine from a common PPS source, 
> what hardware and which Linux would I need?

I'm not aware of any Linux distribution that wouldn't be suitable.

The most common way of feeding PPS is to use a modem control signal on a 
serial port, although a parallel port might have a faster rise time.

Although the hardware to feed the signal is very simple, I'm not sure to 
what extent it is available off the shelf above the chip level.

> David Woolley wrote:
>> C BlacK wrote:
>>> If the timing on client machines needs to be tight, should the ntp
>>> server be an x86 machine with a less than accurate clock
>>> or a ntp server with a very accurate clock.
>>> I want the clients to track closely to server.
>> The clients will almost certainly be the weak link.
>> Also, if you are going sub-millisecond, you need to analyze the client
>> OS, hardware and scheduing in extreme detail.
>> If you want very tight lock of the software clock (still may have large
>> jitters in terms of real world events), you should feed them from a
>> common PPS source, rather than using ethernet for the fine 
>> synchronisation.

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