A small piece of data inserted in order to achieve a desired memory alignment or other addressing property.For example, the PDP-11Unixlinker, 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.[Jargon File](1994-12-21)