On Screen Display (OSD) used in CATV subscriber set-top decoders can be used for many different interactive viewer information services such as Schedule Guides and Sports Scores. Allowing for the required flexibility and functionality of Interactive Information Services, an OSD decoder system must use flexible redefinable data structures and interfacing rituals. This mandates downloadable behavior and data , not just downloadable screen images.
Decades of Information Systems (IS) software development on mainframe and personal computers have shown that mere reprogramability is not enough. IS applications must evolve almost constantly. Staying responsive to user needs while avoiding development bottlenecks requires that IS systems be built from standard parts customized by parameterization and/or nonprocedural specifications rather than custom hand-crafted code. Examples would include Relational Databases and Application Generators.
These IS productivity techniques can be applied directly in headend computers, and scaled to fit within the OSD decoder. Zenith's HT-2000 decoder system applies both techniques to rapidly develop and then deploy Interactive OSD Information applications.