On Fri, 31 Mar 2000, Jean-Marc Sajot wrote:
> Hello,
>
> I am looking for synchronization tools between two LINUX computers (without
> adding Radio cards).
> I know that SNTP (Simple Network Time Protocol) and NTP exists.
> In a first short approach, I notice that the best granularity is only 1 ms.
You can synchronize to or more computers by connecting them using RS-232C.
You have one a master, the others a slave. The master sends 'HZ'
characters per second. The slaves use the interrupt instead of timer
channel 0. The UART FIFOs are disabled so you get one interrupt/character.
Then you can use any method you want to set the slave's time. The time
will now remain synchronous with the master.
This is the 'cheapie' method.
If you want something a bit more robust, you can use CPUs with identical
motherboards. Install a BNC connector, a cap, resistor and two diodes
in place of the CPU board's crystal. Connect them all together to an
external clock-generator. There is no master/slave so any machine can
go down without taking down the rest. Set all the machines to the same
time using whatever method you want. They will stay in sync.
If you don't synchronize the clocks of the computers, they will drift
apart. This would require continuous SNTP correction, which occurs in
steps. These steps might not be acceptable to your applications.
Cheers,
Dick Johnson
Penguin : Linux version 2.3.41 on an i686 machine (800.63 BogoMips).
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This archive was generated by hypermail 2b29 : Fri Mar 31 2000 - 21:00:29 EST