legacy system

jargon A computer system or application program which

continues to be used because of the cost of replacing or

redesigning it and often despite its poor competitiveness and

compatibility with modern equivalents. The implication is

that the system is large, monolithic and difficult to modify.

If legacy software only runs on antiquated hardware the cost

of maintaining this may eventually outweigh the cost of

replacing both the software and hardware unless some form of

emulation or backward compatibility allows the software to

run on new hardware.

(1998-08-09)