California Code, Revenue and Taxation Code - RTC § 6010.9

(a) “Storage media” includes punched cards, tapes, discs, diskettes, or drums on which computer programs may be embodied or stored.

(b) “Computer” does not include tape-controlled automatic drilling, milling, or other manufacturing machinery or equipment.

(c) “Computer program” means the complete plan for the solution of a problem, such as the complete sequence of automatic data-processing equipment instructions necessary to solve a problem and includes both systems and application programs and subdivisions, such as assemblers, compilers, routines, generators, and utility programs.

(d) “Custom computer program” means a computer program prepared to the special order of the customer and includes those services represented by separately stated charges for modifications to an existing prewritten program which are prepared to the special order of the customer. The term does not include a “canned” or prewritten computer program which is held or existing for general or repeated sale or lease, even if the prewritten or “canned” program was initially developed on a custom basis or for in-house use. Modification to an existing prewritten program to meet the customer's needs is custom computer programming only to the extent of the modification.