[Pharo-project] DateAndTime vs TimeStamp

Hi, I am used to using TimeStamp as my default 'point-in-time' class, although it differs only very slightly from DateAndTime. This was not really a very explicit decision, it just sounded/felt right. Now that I am having some timezone issue to sort out, the way DataAndTime's are printed is more helpful. So the question is: why do we have these two, very similar, classes ? Do we need them ? I vaguely remember there is a Seaside directive: do not just TimeStamp (maybe only for portability) ? In short, what is the rationale behind this situation ? Thx, Sven