If any user could create files of arbitrary size, they could fill up the whole disk, making it impossible for anybody else to work. For this reason, it is possible to impose quotas on users which limit the amount of filestore they can use.
On our system, there is a limit on the total amount of filestore you can have (about 5MB), and also on the number of different files you can have (about 2000). If you exceed your quota, you will not be able to create any more files, and will have to remove some existing ones. The quotas we impose are more than adequate for doing your labwork.