While compiling some new software, I received an error mesage saying that it was unable to create /tmp/name because there was no space left. I deleted some large log files in the /root area, then was able to compile without a problem. This concerns me because I am only using 3.4 GB on a 40GB hard drive.

Is there a space limit to particular directories?
Can you think of any other reason why I would run out of space when I am under 10% full?
How can I confirm that I actually have a 40GB hard drive?

Your drive is partitioned. The /root partition might only have 1GB of space allocated to it, /usr might have another 2GB and the rest is allocated to the /home partition.

Depending on the operating system you're running, I find PHPSysInfo a useful script for tracking for diskspace usage amongst the various partitions. You can find the script on http://php.resourceindex.com

From a shell prompt, type:

df -k

To see the list of partitions you have and how much space is used on each of them. 100% means the partition is full, 0% means it is empty. /tmp is often its own partition, and it is usually a small one.

You should also be able to tell from the output of this command the total amount of disk space you have.

Thanks for the help. My drive is patitioned in 4 areas:

/ ~2GB
/usr ~2GB
/var ~1GB
/home ~33GB

The / partition exceeded its limits. I will store large log files and the older backups in the /home area to prevent future problems.