:shim: n. A small piece of data inserted in order to achieve a
desired memory alignment or other addressing property. For
example, the PDP-11 UNIX linker, in split I&D (instructions and
data) mode, inserts a two-byte shim at location 0 in data space so
that no data object will have an address of 0 (and be confused with
the C null pointer). See also {loose bytes}.
-- The AI Hackers Dictionary
magic number n.
[Unix/C; common] 1. In source code
some non-obvious constant whose value is significant to the
operation of a program and that is inserted inconspicuously in-line
(hardcoded), rather than expanded in by a symbol set by a
commented #define....