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[[Category:Ubuntu]][[Category:Linux]]
= About Computer Lab Maintainance =
Knowing which type of programming language to use when automating a task is based upon a programmers knowledge base and experience. In other word, knowing which is the "'''best tool for the task'''". Should the program is be '''compiled''' (like C, C++, etc) for efficient operation? Should program be '''interpreted''' (eg. Shell Script, Perl Script, JavaScript) for ease of programming? Many factors are involved here, but '''shell scripting is definitely an easy way for the administrator to automate routine tasks'''... I will only be discussing Shell Scripting in the WIKI, although, you can access by webpage to learn other programming languages (like C - Course: IPC144)...
One day, the high-school teacher informed me that the computer system was running slower than normal. I asked the teacher when was the last time that the system has been rebooted. The teacher indicated that the system had been up for at least 5 weeks. It is important to note that a server should be rebooted on a periodic basis, since lost running programs (referred to as the computer system's performance may be affected by "'''zombie processes'''"(programs that were completed, but still running as a process) by occur, or "'''memory leaks'''" (unallocated memory due to poor programmingerrors) may affect the computer server's performance. I instructed recommended that the instructor teacher reboot the server once or twice a week, and ... that solved the problem...
By the way, I suspect the cause of the problem was that students were powering-off their terminals (thin clients) instead of properly logging out their accounts...
Problems such as these may occur from time-to-time, and a Linux administrator will be called upon to provide a solution. Let's take the previous problem and add an additional element. Let's assume that the high-school is used throughout the day and night (i.e. night-school). Let's assume that the only time that the system can be rebooted is between midnight and 7 am. Obviously, the high-school teacher (nor myself) want to say up twice a week after midnight to reboot the system. Therefore, it would make sense to have this shell script (run as the "administrator") automatically for a specificied date and time...
... thus we would use '''cron'''. The cron command or utility stands for "'''Chronograph'''" and is a '''time-based scheduler for programs''' (like shell scripts).
Here is a link to a resource on how to use cron: [http://www.thewebhostinghero.com/tutorials/linux-cron.html http://www.thewebhostinghero.com/tutorials/linux-cron.html]
= Additional Resources =
Here is a link to Edubuntu's Documentation of the LTSP server:
[http://doc.ubuntu.com/edubuntu/edubuntu/handbook/C/server.html http://doc.ubuntu.com/edubuntu/edubuntu/handbook/C/server.html]