Computer Time Synchronization
A Beginner's Guide to Network Time Protocol (NTP)
Warning! This Page contains obsolete information.
Other Time Software
When I started looking for time synchronization software I wasn't particularly
concerned with highly accurate time but I did want all my computers on the
same time. It was my intent to use the computer with the most accurate
clock as the master and sync all the others to it. If I could find an easy
way to automatically keep the master time reasonably accurate great but
if I had to manually reset it's clock periodically I was prepared to do that.
I'm not using any time sensitive protocols and I thought this would be
fine for my needs.
The Unix boxes were trivial. Unix comes with timed which keeps
the times of computers on a LAN synched. All that's necessary
is to start timed at boot time on the master time computer with "timed -M
-F hostname" where hostname is the name of localhost.
With timed started
on the other computers without any arguments, they will act as clients to
the master. timed does not need a master server. When run without a master
the computers will negotiate and presumably use an average or weighted
The problem was synchronizing the Windows NT computers with the Unix systems.
In my first search, I only found one free
product that claimed to be a Windows equivalent of timed. This ran as
an NT service but had minimal
documentation and no options to force it to be a master or client. I gave
it a try anyhow. After several days, it was apparent that the time on
both NT computers was drifting away from the time on the Unix systems and
from each other.
I started another search. This took me to the National Institute of
Standards and Technology, NIST,
Your Computer Clock page. This included NIST provided public domain
software for Windows computers which would set my Windows PC clocks from
one of the NIST or other public time servers. This free software did not run
as an NT service or provide a service for other computers to synchronize to.
The NIST page also included a list of software publishers that had
NTS (Network Time Service) products.
The NTS products ranged from free to nearly a thousand dollars.
Though I have spent many thousands of dollars on computer
software over the years, recently I find myself increasingly less
willing to spend big bucks on proprietary products. It's clear
that in many areas there are open source products that are as
good or better than proprietary counterparts. If I don't already
own a commercial product and have the knowledge to use it, I now
look first for open source solutions, then freeware and then
shareware. I'll only buy commercial products, if I have a clear
need that can't be met by alternative products.
The NIST list has fourty some products but except for some
expensive commercial products, none that ran as an NT service and
provided both client and server sides to the time synchronization
problem. The NIST list had only Window and Macintosh products
with no Unix products listed. I book marked several that looked
promising but only downloaded and installed one product,
from One Guy Coding. This freeware program was like an advanced
version of the NIST product and runs as a system tray item.
Automachron can also synchronize an NT computer to a Unix
computer running Time Protocols's timed or Network Time Protocol's
ntpd but I did not realize this until after I had an NTP server,
as discussed below, set up.
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