  In charged current deep inelastic scattering charm is dominantly produced in
scattering events on strange quarks, thereby allowing for an experimental
determination of the nucleon's strange sea density. A measurement of the energy
spectrum of final state charm fragments (D-mesons) determines the charm
fragmentation function at spacelike scales considerably below typical e^+e^-
c.m.s. energies. NLO corrections to the naive s -> c parton model production
picture are important and well understood.
