1. A hybrid computing environment for direct injection of data to be transferred, the hybrid computing environment comprising a host computer having a host computer architecture, a plurality of accelerators having an accelerator architecture, the accelerator architecture optimized, with respect to the host computer architecture, for speed of execution of a particular class of computing functions, the host computer and the accelerators adapted to one another for data communications by a system level message passing module, each accelerator further comprising a Power Processing Element (‘PPE’) and a plurality of Synergistic Processing Elements (‘SPEs’), the hybrid computing environment comprising computer program instructions capable of: reserving, by each SPE of an accelerator, a slot in a shared memory region accessible by the host computer; loading, by each SPE of the accelerator from local memory of the accelerator into local memory of each SPE of the accelerator, a portion of data to be transferred to the host computer; executing, by each SPE of the accelerator in parallel, a data processing operation on the portion of the data loaded in local memory of each SPE of the accelerator; and writing, by each SPE of the accelerator, the processed data to each SPE of the accelerator' assigned slot in the shared memory region.