A heat-sensitive composition of the positive type comprising a polymeric binder and a solubility inhibitor, wherein the said solubility inhibitor consists of an organometallic compound, with the exclusion of the metallocenes, an organic salt or an organic complex of an inorganic salt of a metal belonging to the group IIIA or transition group of the periodic system of the elements. Provision is made for referencing and dereferencing execution contexts and thereby providing execution isolation across contexts. The data inversion circuit is further configured to support a bypass mode of operation.