External reengineering of 'Catalogo Bibliografico Trentino': lessons learned

Many programs are now in use since more than a decade. They control valuable information, but their user interface is still based on early technology, and their use is not considered user-friendly any more (if it ever was!). Often their code is not documented, and to put the hands in their code is a very expensive and error-prone task. It would therefore be desirable to be able to apply, possibly with little effort, some aesthetic surgery on them without risking to compromise their health. In a poster presented at the WWW'95 in Darmstadt, [ron95] we suggested that WWW can provide safe and relatively inexpensive means to build a better user interface to them. We built an interface for such an application: an information system for all the public libraries of a small region in northern Italy, well known for its beautiful mountains and ski resorts. The CBT system (Catalogo Bibliografico Trentino) was established one decade ago on a proprietary systems to serve all libraries of the Trento Province (6000 Kmq), using the Dobis-Libis system. IBM 3270 terminals were placed in the civic libraries (even in the smallest villages) and connected through an X25 network. Libraries of the local University, and research centers also belong to this system. The CBT system is also reachable via telnet through a gateway (which converts VT100 emulation in the 3270 protocol). Of course, the (character based) user interface remains the one designed one decade ago, and typically users find the system rather annoying to use, especially through the telnet connection. We therefore built a translator which on one side establishes (and keeps alive) a permanent connection with the CBT system through some of the available telnet ports, and on the other side responds to CGI scripts invoked through the HTTP server. The system is now in use, and received thankful attention from frustrated users of the original system. Aim of our contribution to the workshop is to share the lessons we learned in developing our interface. We will sketch here a short summary of them.