[ntp:questions] Re: Initial Setting

David L. Mills mills at udel.edu
Tue Apr 26 03:30:29 UTC 2005


Guys,

1. Unlike Unix, the NTP timestamp format is a 64-bit unsigned integer.

2. Please see the white paper "The NTP Timescale and Era Numbering" on 
the NTP project page. Life does not end in 2036.

Dave

David Schwartz wrote:
> "mgrd" <mgrd at gmx.net> wrote in message 
> news:d4jm2p$4m1$02$1 at news.t-online.com...
> 
> 
>>David Schwartz wrote:
> 
> 
>>>"mgrd" <mgrd at gmx.net> wrote in message
>>>
>>>>why not run `netdate' before starting xntpd to sync first?
>>>
>>>That assumes you can find usable servers.
> 
> 
>>True.
>>But where is the difference between finding a usable server while
>>running `netdate' and while/after starting xntpd (regardless if while
>>bootstrapping or afterwards).
> 
> 
>     The NTP protocol is a current, well-documented, support protocol with 
> lists of publically accessible servers.
> 
> 
>>>There's also the problem that RFC868 is internally inconsistent and not 
>>>sufficient to document a usable time protocol.
> 
> 
>>Hmm, I just read RFC868.
>>I can't get the inconsistency. Could you give me a hint?
>>But the insufficiency is obvious since it's no very detailed.
> 
> 
> "The most important thing is, the time is the number of seconds since 00:00 
> (midnight) 1 January 1900 GMT, such that the time 1 is 12:00:01 am on 1 
> January 1900 GMT; this base will serve until the year 2036."
> 
>     A 32-bit signed value can represent rougly plus or minus 2^31 seconds, 
> which is about 68 years. This would mean that this protocol can represent 
> times from about 1832 to 1968. The examples include:
> 
> "2,629,584,000 corresponds to 00:00 1 May 1983 GMT", and
> "-1,297,728,000 corresponds to 00:00 17 Nov 1858 GMT"
> 
>     Do you know any way for a 32-bit signed integer to get to 2.6 billion?
> 
> 
>>But where's the relationship between this and the problem of the OP?
> 
> 
>     The point is that 'netdate' is not really all that useful anymore. It's 
> not likely that he can easily find a list of servers that he can query. A 
> more useful tool would be one that connected to a few web servers and got 
> the time/date from the header.
> 
>     DS
> 
> 



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