OPS335 Assignment 1

Keeping accurate time on a Linux-based computer is one of the functions assigned to the system administrator. Correct time will ensure log records have accurate time stamps and that scheduled processes (eg. cron jobs) will run precisely when intended. Linux's time keeping toolchest includes the following:

• date
• hwclock
• daytime
• rdate
• ntpdate
• ntpd
• chrony
• radios

For this assignment you are to investigate each of the above mentioned time keeping methods on your Fedora 13 Linux PC. 

date

1. Show real examples of how to use this command to set your Fedora system clock.
2. Comment on the accuracy of the time set using this method.
3. State advantages and disadvantages of this method.

hwclock

1. Show real examples of how to use this command to set your Fedora system clock.
2. Show real examples of how to use this command to set your hardware clock.
3. Comment on the accuracy of the time set using this method.
4. State advantages and disadvantages of this method.
5. Comment on the accuracy of the hardware clock built into the mainboarrd of your computer.

daytime

1. Set up your Fedora PC to be a daytime server (through xinetd).
2. Set up a virtual machine and configure it to set its clock to the host using a local rc file and netcat at boot time.
3. Find other hosts on the Internet that will let you use this method to set your clock. Which one did you use?
4. Comment on the accuracy of the time set using this method.
5. State advantages and disadvantages of this method.
6. Be sure to list any files you modified and or created. Specifically inside /etc/init.d /etc/xinetd.d directory.

rdate

1. Show how to use rdate in a cron job to set your virtual machine's clock to the host's time. Try this out - don't just guess at the answer.
2. Find other hosts that will let you use rdate to set your clock. Which host did you use?
3. Comment on the accuracy of the time set using this method.
4. State advantages and disadvantages of this method.
5. Be sure to list any files you modified and or created.
6. What port(s) are used by this method?

ntpdate

1. Use ntpdate command in a cron job to set your virtual machine's clock to the time on any ntp server.
2. Comment on the differences between stratum-1, stratum-2, stratum-3, etc. time servers.
3. Comment on the accuracy of the time set using this method.
4. State advantages and disadvantages of this method.
5. Be sure to list any files you modified and or created.
6. What port(s) are used by this method?

ntpd

1. Set up an ntp server on your Fedora host. Be sure to enable logging and statistics files.
2. Find an open and free stratum-1 time server to use on your host.
3. Show log records when starting your ntp server.
4. Show and explain the contents of your ntp server's statistics file.
5. Set up an ntp server on your Fedora VM and use your host as its time server.
6. Use the ntpstat command on both host and VM to demonstrate that everything is working properly.
7. Comment on the accuracy of the time set using this method.
8. State advantages and disadvantages of this method.
9. Explain how you could set up another VM as a stratum-3 server.

chrony

1. Install and configure chrony on your Fedora host and your VM. Then use chrony on your VM to synchronize its clock to the host.
2. Explain precisely how you did this. Show edited files and specific commands used.
3. Comment on the accuracy of the time set using this method.
4. State advantages and disadvantages of this method.

radios

1. In order to test this method you'll need some sort of radio card that will receive GPS satellite signals. I use an old Garmin Etrex portable receiver that connects to my computer's serial port. Since most students probably won't have such a device it would be ok to just write a paragraph or two about this method. i.e. is it accurate, easy to set up, expensive, etc.

Finally, provide conclusions to your experimentation. i.e. which method is most accurate? least accurate? most reliable? least reliable? etc. Perhaps a table could be used to summarize your results?

NOTES:

This is a hands-on assignment to be done by each student individually (this is NOT a group assignment).

Please submit this assignment in formal written form according to instructions posted on your teacher's web page and also email an electronic copy to him/her.

This assignment is worth 10% of your final grade.