Gary is a custom gate array chip introduced in the Amiga 500 and 2000 models, named after Commodore engineer Gary Boone. It functions as an address decoder and system glue logic chip, replacing numerous discrete TTL components found in earlier Amiga 1000 designs. Gary handles address decoding for the CIA chips, parallel port, and other system resources, working alongside the main custom chips (Paula, Denise, and Agnus) to manage system arbitration.