This was back in the 90s... we figured out a simple way to make 'empty' files using the spacebar ascii and qbasic. We'd have a simple interface, flashing cursor, and you'd type in a number; it would then create an 'empty' file of that many MB.

Of course being 14 yr old little shits, we wondered, how big can the file be? Someone created a file big enough that first it filled the student partition; then the teacher partition; then the temp partition; then the system partition, at which point the entire network slowed to a transfer speed of a couple of bytes. When we realised we could do this, it was happening several times a week.

After that, anyone caught with a blank screen and flashing cursor got in deep shit. They deleted the attrib command so we couldn't un-read-only / un-hidden things, but we just copied it from our own DOS at home and brought it in on a floppy drive