JohnC
December 4, 2002, 12:34 pm
Why set time?
Firstly, it doesn't matter that you do - if you work in isolation from the rest of the world, you don't send email or write letters or make use of the date orientated filing system on your PC. It does matter if you want to keep emails in order, for instance, and make sure that you recipients can read them in order. So let's say for the purposes of this argument that setting accurate time on your PC is a good thing. And as PC clocks are only accurate to seconds per day at best and get worse as the batteries age it may be a good idea to set your PC time whenever you're online.
Let's define time
It's all down to standards again (and this one BillG can't hijack!). Time is measured from the Greenwich Meridian and nowadays is called UT – Universal Time. Time is then offset positive or negative against this meridian as you travel round the world. A further seasonal offset is used where daylight saving is applied. The rules for all of this can be found at http://greenwichmeantime.com. We won't repeat them here because you presumably know which time zone you're in and when daylight saving applies.
Setting up the PC
For Windows users the Control Panel/Date and Time/Time Zone should be set correctly for where you are in the world. Daylight saving should also be enabled if it applies to your location. For Linux users , this is set in the Services/Date and Time area. If you don't set the PC clock correctly then you'll be in trouble from email users who (like me) prefer to see their mail in the correct order.
Setting up the time synchronization
What you need to do is to reference an atomic clock – there are a few of them round the world and they set primary time servers on the Internet. From these, in order to maintain network traffic to a reasonable level, secondary time servers set themselves against the primary servers. The way this is done is NTP – Network Time Protocol. It is these you can access to check your PC clock. How you access them is up to you. Windows 2000 and XP have an internal time synchronization program that you can set to run automatically at intervals. On XP the interval becomes 7 days by default,but as your PC clock is only accurate to seconds a day you may like to maintain a regime of manually checking more frequently, or by using one of the methods described below and switching off the native timesync program. NT, and 9x users have no such inbuilt program. On Linux you can specify the time checking interval within the single screen in the system area – much simpler.
There's also the w32tm.exe program options that I'm not covering here – if you're a network admin presumably you know all about these.
If you don't want to accept the windows default system or you are on an OS that hasn't got the facility, then you have to get a program to do it for you. There are many around both free and paid for. The free one I've been using is Automachron (180kb) from http://oneguycoding.com/automachron/ and Atomic Time (67kb) from http://schmail.com/atomictime/ . Atomic time has its own list of NTP servers embedded, with Automachron you have to find one and you can do that here - http://www.eecis.udel.edu/~mills/ntp/clock2.html but first consult the main explanatory page here - http://www.eecis.udel.edu/~mills/ntp/servers.html . Simply put the relevant address into any of the programs and your PC clock will be set. You can consult the whole range of information about NTP and time at http://www.eecis.udel.edu/~ntp/ which will give you enough information about time and then some to spare.
And that's it
This has been edited for typos only.
Firstly, it doesn't matter that you do - if you work in isolation from the rest of the world, you don't send email or write letters or make use of the date orientated filing system on your PC. It does matter if you want to keep emails in order, for instance, and make sure that you recipients can read them in order. So let's say for the purposes of this argument that setting accurate time on your PC is a good thing. And as PC clocks are only accurate to seconds per day at best and get worse as the batteries age it may be a good idea to set your PC time whenever you're online.
Let's define time
It's all down to standards again (and this one BillG can't hijack!). Time is measured from the Greenwich Meridian and nowadays is called UT – Universal Time. Time is then offset positive or negative against this meridian as you travel round the world. A further seasonal offset is used where daylight saving is applied. The rules for all of this can be found at http://greenwichmeantime.com. We won't repeat them here because you presumably know which time zone you're in and when daylight saving applies.
Setting up the PC
For Windows users the Control Panel/Date and Time/Time Zone should be set correctly for where you are in the world. Daylight saving should also be enabled if it applies to your location. For Linux users , this is set in the Services/Date and Time area. If you don't set the PC clock correctly then you'll be in trouble from email users who (like me) prefer to see their mail in the correct order.
Setting up the time synchronization
What you need to do is to reference an atomic clock – there are a few of them round the world and they set primary time servers on the Internet. From these, in order to maintain network traffic to a reasonable level, secondary time servers set themselves against the primary servers. The way this is done is NTP – Network Time Protocol. It is these you can access to check your PC clock. How you access them is up to you. Windows 2000 and XP have an internal time synchronization program that you can set to run automatically at intervals. On XP the interval becomes 7 days by default,but as your PC clock is only accurate to seconds a day you may like to maintain a regime of manually checking more frequently, or by using one of the methods described below and switching off the native timesync program. NT, and 9x users have no such inbuilt program. On Linux you can specify the time checking interval within the single screen in the system area – much simpler.
There's also the w32tm.exe program options that I'm not covering here – if you're a network admin presumably you know all about these.
If you don't want to accept the windows default system or you are on an OS that hasn't got the facility, then you have to get a program to do it for you. There are many around both free and paid for. The free one I've been using is Automachron (180kb) from http://oneguycoding.com/automachron/ and Atomic Time (67kb) from http://schmail.com/atomictime/ . Atomic time has its own list of NTP servers embedded, with Automachron you have to find one and you can do that here - http://www.eecis.udel.edu/~mills/ntp/clock2.html but first consult the main explanatory page here - http://www.eecis.udel.edu/~mills/ntp/servers.html . Simply put the relevant address into any of the programs and your PC clock will be set. You can consult the whole range of information about NTP and time at http://www.eecis.udel.edu/~ntp/ which will give you enough information about time and then some to spare.
And that's it
This has been edited for typos only.