:slack: n. 1. Space allocated to a disk file but not actually used
to store useful information. The techspeak equivalent is `internal
fragmentation'. 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}.
-- The AI Hackers Dictionary