The invention relates to a plasma deposition process for producing an optical preform, which is characterized by a cladding glass layer having a non-round internal cross-section together with high fluorine doping and axially and radially specified dopant distribution, which in the simplest case is as uniform as possible. A processor of a computer system identifies a first generation of change-affected parts of one or more computer programs, where each identified part is affected by a change to the basepoint variable. The method creates an additional parity error signal which is not specified under the IEEE 802. The first set of working zones are disposed on a first layer of the substrate and have at least two working zones diagonally opposed and spatially offset relative to one another.