slack
slack: n. 1. Space allocated to a disk file but not actually
used to store useful information. The techspeak equivalent is
`internal fragmentation'. Antonym: hole. 2. In the theology of
the Church of the SubGenius, a mystical substance or quality that
is the prerequisite of all human happiness.
Since Unix files are stored compactly, except for the unavoidable
wastage in the last block or fragment, it might be said that "Unix
has no slack". See ha ha only serious.