Help Please, Looking for a data row hash check digit Algorithm

Greetings All, Many moons ago I worked on an Informix data warehouse system where each row had an integer hash total check digit. I cannot recall if this digit was calculated prior to the row being loaded/inserted or at the time of loading/insertion. The rows' hash total was used to circumvent unnecessary updates of unchanged rows during 'intelligent loading'. I'm hoping someone can offer guidance or an example of the type of code that would calculate such a 'hash total'. It was capable of indicating a simple change like the up-shifting of a letter. Does this ring a bell with anyone? Has Informix long since provided such a utility ? TIA, Tim