Linear differential operators over a rational function field can be factored, just like polynomials over number fields. The main difference between these two, however, is that the multiplication of differential operators is non-commutative. The order of the multiplication is therefore important. There are a few algorithms known for determining a class of factorisations. The one that currently is being implemented uses factorisations over Laurent series rings. These can be used later for the factorisation over rational fields. In this talk I plan to talk about the series implementations and the ideas behind them, and mention some similarities with the number theory case.