Limits on your account

There are certain limits on your Linux account, which are imposed to protect both the system, other users, and yourself. You can raise some of these limits yourself. One of the limits can be raised only by the system administrator.

First of all, there is a limit on the amount of disk space that you can use in your home directory. For new accounts, the limit is set to 500 MegaBytes. You can check your quota and how much space you have left by giving the command "fs listquota" on the command line. (This command lists disk space in units of 1-kilobyte blocks, so "500000" means 500 megabytes.) If you run out of space, the only recourse is to ask the system administrator, Scotty Orr, for more space. The default limit of 500MB should be plenty for most people. However, requests for reasonable amounts of additional space will be considered.

The second type of limit is limits on programs that you run. These limits can keep a program from running forever, for example. The limits that are imposed are:

         CPU time:    10 minutes
         Stack Size:  16 Megabytes

The CPU time limit is a limit on the amount of actual computing time on the computer's processing unit that a program can use. If it exceeds this limit, it will be killed without warning. Ten minutes is a lot of time. If you are running a program that really does need more CPU time, you can use the command

         ulimit -t unlimited

to remove the time limit completely. You must do this in a command-line window. You must run the program from the same window, since the ulimit only applies to one command-line window. Alternatively, you could add this command to the file named .bashrc in your home directory. This will make the change automatically in all your log-ins.

The limit on stack size is there mainly to prevent programs from doing infinite recursion. The 16 megabyte limit shouldn't be a problem, but, again, you can remove the limit by saying

         ulimit -s unlimited

However, please don't do this without thinking about it, since infinite recursion is one of the things that can cause a problem on a Linux computer.