Re: Port Informix 3.3 -> Current Version. How Difficult?

In article <4js8tn$380@leithaus.leitess.com>, broswell@syssrc.com says... >One side of the debate suggests porting the Informix 3.3 to a current >version running on a Pentium and SCO Unix. This side is claiming that >the port is trivial. > >The other side is claiming that the architecture of the new version of >Informix is completely different and the system need a full rewrite >just to port the system. Then, as long as we are rewriting, we should >use SQL Server and NT. We recently completed such a project. We converted upwards of a million lines of C code from the ALL-II libraries, supported under Informix 5 but not supported in subsequent versions. If you're talking about C code, I think I can address the subject. Our effort did -not- require a full rewrite of the system. Generally speaking, any given ALL-II function call can be replaced by an equivalent ESQL statement. We had to write some libraries to support functionality no longer supplied with the ESQL product (eg, the dbfield() function), but when you compare that with rewriting an entire product line from scratch, it was easy. On the other hand, conversion was not trivial. It does require the commitment of a lot of resources, both in doing the conversion and in testing the results. But, in my estimation, it takes a lot less time and effort to convert an existing application from Informix 3.3 to a current version of Informix than it would take to rewrite it from scratch. If your system is a 4GL system, I do not have as close an acquaintance as I do with C, but I would tend to believe the situation is similar - converting that version of 4GL code to Informix 5 or 7 (or whatever) has to be a lot easier than rewriting everything from scratch. If your system is primarily written in Informer, Perform, and Ace, then it's still not a "trivial" port by any means. But there are tools to convert Informer/Ace "read into" statements to SQL, and Perform screens are almost exactly the same as Informix 3.3 perform screens. You may have to tune things here and there after you convert them, but that's got to be faster and easier than rewriting from scratch. -- William Harris william@carsinfo.com CIS (CARS Information Systems) 4000 Executive Park Drive Cincinnati, OH (USA) 45241