In this paper a ''PD''-program package (PD-pp) for the calculations of
isobaric phase equilibria in a multicomponent system by means of a pe
rsonal computer is presented. The PD-pp is based on the solution model
for phases with several components and sublattices. The main thermody
namic relations involved in PD-pp are introduced. The selected results
of equilibrium calculations in the iron based systems and computing t
ime needed are added as an example.