Re: Time Puzzle (and DST update about the web link)

No we do not use NTP. Just to stress, I am not concerned about the time being off on our system. It seems accurate to me. Further, we have made no significant changes to our system in months.

What is puzzling to me is how I can have a record of myself signing in from a machine whose time I am also confident of and have a time discrepancy of multiple hours when both are in the same time zone and set as such.

==============================================

Karl,
Are you running Network Time Protocol (NTP)? Did you have a
misconfigured NTP server in your NTP configuration?

Without Network Time Protocol (or another clock discipline method), most
clocks will use the AC cycle (60 HZ in the USA) as their reference
frequency and will drift wildly depending on the quality of the power.
Power conditioning will help, but NTP should keep the clocks in sync
with each other. There are NTP hardware devices (appliances) that
receive radio signals that are broadcast by governments that keep your
clocks in sync with a national standard clock.

Also, if you lose power and switch to a local generator, the quality of
the power from a local generator tends to vary frequency by the load of
the generator, this will drive the clocks crazy too. I found this out
when I ran my alarm clock off a generator that was running at 62 HZ. By
morning, my alarm clock was significantly ahead of my battery-powered
clocks!


Edward Davignon
Lead Analyst - Distributed Systems
Utility Shared Services - IT
Energy East Corporation

-----Original Message-----
From: IBM AIX Discussion List [mailto:aix-l@xxxxxxxxxxxxx] On Behalf Of
Karl Jones
Sent: Friday, February 02, 2007 10:03 AM
To: aix-l@xxxxxxxxxxxxx
Subject: Re: Time Puzzle (and DST update about the web link)

I have not been experimenting with TZ. Further, in one instance, the user is me from a machine which I know is set for the same time zone. Nevertheless it is the only lead I have so far so I will look into it.

Andrew.Townsend@xxxxxxxxx wrote:
> Let me guess, you're experimenting with the TZ ?
>
> I am testing the chtz command and I have seen that same thing as well.
>
> By the way, if you are looking at this website that shows you how to
change
> the timzone information to reflect the upcoming changes in Daylight
Savings
> Time (only for those of use that aren't at the supported level):
>
> http://www-1.ibm.com/support/docview.wss?rs=0&uid=isg3T1000252
>
> The command on the website shows this command (For EST):
>
> chtz TZ=EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00
>
> The command should be:
>
> chtz EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00
>
> I called IBM and told them so hopefully it will be changed on the
website
> soon.
>
> Once the command is run, check the /etc/environment and look at the
TZ=
> line. If you use the command shown on the website you will see:
>
> TZ=TZ=EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00
>
> what you want to see is:
>
> TZ=EST5EDT,M3.2.0/2:00:00,M11.1.0/2:00:00
>
> Drew
>
>
>
>

> Karl Jones

> <kjones@stpaullin

> ocpt.com>
To
> Sent by: IBM AIX aix-l@xxxxxxxxxxxxx

> Discussion List
cc
> <aix-l@Princeton.

> EDU>
Subject
> Time Puzzle

>

> 02/01/2007 04:47

> PM

>

>

> Please respond to

> kjones@stpaullino

> cpt.com

>

>

>
>
>
>
> I am puzzled by the date stamps here. How is this possible?
>
> Last unsuccessful login: Thu Feb 1 20:58:34 2007 on ssh from
> 221.208.160.11
> Last login: Thu Feb 1 21:32:06 2007 on ssh from karl-jones
> [snip]
> F50:/ # date
> Thu Feb 1 15:32:40 CST 2007
>
>

Relevant Pages

  • Re: Sun Solaris Time Servers?
    ... before it will accept a newly init'd time source's time info for NTP ... There are some nice non-atomic NTP clocks at the low end, ... You can make an NTP server sync via GPS for a *lot* less than $3,000. ... You can buy cesium clocks on eBay quite easily, but the life of the tube ...
    (comp.unix.solaris)
  • Re: Successful remote AES key extraction
    ... >Dan's attack doesn't require synchronized clocks. ... to within microseconds. ... The reported AES timing attack requires the measurement of variations ... NTP clock synchronization is also affected by variations ...
    (sci.crypt)
  • Re: Sun Solaris Time Servers?
    ... before it will accept a newly init'd time source's time info for NTP ... There are some nice non-atomic NTP clocks at the low end, ... It would be very easy to turn an old Sun into a decent NTP server just by putting a GPS receiver on the serial port and using the 1 pps output from one. ... You can buy cesium clocks on eBay quite easily, but the life of the tube is limited and are expensive to replace. ...
    (comp.unix.solaris)
  • Re: Time Puzzle (and DST update about the web link)
    ... Are you running Network Time Protocol (NTP)? ... but NTP should keep the clocks in sync ... I am testing the chtz command and I have seen that same thing as well. ...
    (AIX-L)
  • Clock drift in 6800 domains
    ... I need some insight into a clock drift issue on a 6800. ... If NTP is run on the domains themselves, ... step the clocks forward some number of seconds, ... The SCs are synced via SNTP to a good time source, ...
    (SunManagers)