Compressed recording data is DMA-transferred to a receiving buffer unit
via a system bus one word each. It is DMA-transferred from the receiving
buffer unit to a DECU via the system bus. It is developed based on
hardware by a decode circuit in the DECU, and stored in a line buffer. It
is DMA-transferred to a local memory via a local bus when it reaches
predetermined bytes. The recording data stored in the local memory is
DMA-transferred to the DECU via the local bus, DMA-transferred to a head
controlling unit and DMA-transferred to a recording head.