  Quantum memories can be regarded as quantum channels that transmit
information through time without moving it through space. Aiming at a reliable
storage of information we may thus not only encode at the beginning and decode
at the end, but also intervene during the transmission - a possibility not
captured by the ordinary capacities in Quantum Shannon Theory. In this work we
introduce capacities that take this possibility into account and study them in
particular for the transmission of quantum information via dynamical semigroups
of Lindblad form. When the evolution is subdivided and supplemented by
additional continuous semigroups acting on arbitrary block sizes, we show that
the capacity of the ideal channel can be obtained in all cases. If the
supplementary evolution is reversible, however, this is no longer the case.
Upper and lower bounds for this scenario are proven. Finally, we provide a
continuous coding scheme and simple examples showing that adding a purely
dissipative term to a Liouvillian can sometimes increase the quantum capacity.
