from
Jargon File (4.4.4, 14 Aug 2003)
padded cell
n.
Where you put {luser}s so they can't hurt anything. A program that
limits a luser to a carefully restricted subset of the capabilities of
the host system (for example, the rsh(1) utility on USG Unix). Note
that this is different from an {iron box} because it is overt and not
aimed at enforcing security so much as protecting others (and the
luser) from the consequences of the luser's boundless naivete (see
{naive}). Also padded cell environment.