Disk Quota
Even nowadays, hard disks are not unlimited and therefore neither is your personal disk space. On most systems, disk quota are implemented to prevent disks from filling up completely. This is certainly so on/for the file system your home directory /home/loginname is located on.
Ask for more Quota
If you run out of disk space, you can ask for more quota with your system group representative. He/She administers the quota for the research group. In case of (long) absence of this person you can also ask helpdesk, but her decision/action is only temporary until the system group representative is back.
Funny Quota Messages
"Block limit reached on /home/user" means that you are over your quota on the file system that is currently mounted on that "/home/user" mount point even if you are not the "user" that is shown. Your (home) directory is probably located on that same file system, but this message uses the directory that was mounted first from that file system to denote the file system. Some say this is a bug, but opinions vary ;-)
Also the command quota -v
has this peculiarity on some OS versions.
Check your Quota
On the student computer lab documentation you can find more detailed explanation about how to check where your quota is being used for. In this way you can easily decide whether to clean up or to ask for more quota.
Disk Space without Quota
On some file systems, you can store files and directories without quota being enforced.
Most of these file systems are unmanaged: you have to have the discipline to clean up yourself or otherwise the disk will fill up quickly. Typically these unmanaged writable file systems without quota are accessible via /export/home1/NoCsBack/... (or .../home2/... or home3 ...)
Do notice that these file systems are typically not being backupped and to double-stress that, the only writable (sub-)directories on them are located inside the NoCsBack directory.
To be able to quickly determine who has what where, we periodically register how much is used on each of these file systems in /var/log/cs-acct/quota.NoCsBack on the machine the file system is located on. This is only checked when needed though.
Some of these writable file systems are too important to be left completely unmanaged. To keep a little overview and to detect abuse, we periodically register how much is used on each of these file systems and this is reviewed regularly.