The hexadecimal word-fill pattern for freshly allocated memory under
a number of IBM environments, including the RS/6000. Some modern debugging
tools deliberately fill freed memory with this value as a way of converting
heisenbugs into Bohr bugs.
As in Your program is DEADBEEF
(meaning gone, aborted,
flushed from memory); if you start from an odd half-word boundary, of
course, you have BEEFDEAD. See also the anecdote under
fool and
dead beef attack.