Method of processing a context for execution

A data controller in a storage drive, said data controller comprising:

• a buffer for storing data transferred in response to execution of a direct memory access (DMA) transfer request;
• a host address pointer pointing to a current location in said buffer;
• a retrieval channel device included in said data controller;
• and
• said retrieval channel device configured to:
• fetch a context that describes a direct memory access (DMA) transfer requested by a host computer to which said storage drive is coupled, said DMA requesting a transfer of a particular amount of data;
• determine a current capacity of said buffer for transferring data;
• determine whether said current capacity exceeds a threshold;
• generate an instruction to transfer a second amount of data to complete at least a portion of said requested DMA transfer in response to said retrieval channel device determining whether said current capacity exceeds said threshold;
• adjust said current capacity by said second amount of data;
• assert said instruction;
• and
• adjust said host address pointer by said second amount of data.

A data storage device that includes a data controller, said data storage device comprising:

• means for receiving from a peripheral device that is coupled to said data storage device a DMA command that requests a data transfer of a first amount of data;
• means, responsive to said means for receiving, and performed independently of feedback from any DMA data movement block, for:
• (i) determining a current location in said buffer utilizing a host address pointer that points to said current location;
• (ii) determining a current capacity of said buffer for transferring data;
• (iii) determining whether said current capacity exceeds a threshold;
• (iv) generating an instruction, by said data controller, to transfer a second amount of data to complete at least a portion of said DMA command if it is determined that said current capacity exceeds said threshold;
• (v) adjusting said current capacity by said second amount of data;
• (vi) asserting said instruction;
• and
• (vii) adjusting said host address pointer by said second amount of data to point to a new current location.

A computer program product in a data storage device that includes a data controller, said computer program product comprising:

• instructions for receiving within said data storage device, from a peripheral device that is coupled to said data storage device, a DMA command that requests a data transfer of a first amount of data;
• instructions, responsive to said instructions for receiving, for:
• (i) determining a current location in said buffer utilizing a host address pointer that points to said current location in said buffer;
• (ii) determining a current capacity of said buffer for transferring data;
• (iii) determining whether said current capacity exceeds a threshold;
• (iv) generating an instruction, by said data controller, to transfer a second amount of data to complete at least a portion of said DMA command if it is determined that said current capacity exceeds said threshold;
• (v) adjusting said current capacity by said second amount of data;
• (vi) asserting said instruction;
• and
• (vii) adjusting said host address pointer by said second amount of data to point to a new current location.