Delta
1. A quantitative change, especially a small or incremental one (this use is general in physics and engineering).
"I just doubled the speed of my program!"
"What was the delta on program size?"
"About 30 percent."
(He doubled the speed of his program, but increased its size by only 30 percent.)
2. [Unix] A
diff, especially a
diff stored under the set of version-control tools called SCCS (Source Code Control System) or RCS (Revision Control System).
See
change management.
3. A small quantity, but not as small as
epsilon.
The jargon usage of
delta and
epsilon stems from the traditional use of these letters in mathematics for very small numerical quantities, particularly in "epsilon-delta" proofs in limit theory (as in the differential calculus).
The term
delta is often used, once
epsilon has been mentioned, to mean a quantity that is slightly bigger than
epsilon but still very small.
"The cost isn't epsilon, but it's delta" means that the cost isn't totally negligible, but it is nevertheless very small.
Common constructions include "within delta of ---", "within epsilon of ---": that is, "close to" and "even closer to".
[
Jargon File]