live data: n. 1. Data that is written to be interpreted and takes over program flow when triggered by some un-obvious operation

:live data: n. 1. Data that is written to be interpreted and takes
over program flow when triggered by some un-obvious operation, such
as viewing it. One use of such hacks is to break security. For
example, some smart terminals have commands that allow one to
download strings to program keys; this can be used to write live
data that, when listed to the terminal, infects it with a
security-breaking {virus} that is triggered the next time a
hapless user strikes that key. For another, there are some
well-known bugs in {vi} that allow certain texts to send
arbitrary commands back to the machine when they are simply viewed.
2. In C code, data that includes pointers to function {hook}s
(executable code). 3. An object, such as a {trampoline}, that is
constructed on the fly by a program and intended to be executed as
code. 4. Actual real-world data, as opposed to `test data'.
For example, "I think I have the record deletion module
finished." "Have you tried it out on live data?" This usage usually
carries the connotation that live data is more fragile and must not
be corrupted, or bad things will happen. So a more appropriate
response to the above claim might be: "Well, make sure it works
perfectly before we throw live data at it." The implication here
is that record deletion is something pretty significant, and a
haywire record-deletion module running amok on live data would
probably cause great harm.
-- The AI Hackers Dictionary