System for transferring data having a generator for generating a plurality of transfer extend entries in response to a plurality of commands received
First Claim
1. A method of data transfer between a peripheral device and a host computer, the method comprising the steps of:
- (A) generating a plurality of transfer extend entries in the peripheral device in response to a plurality of commands received from the host computer;
(B) arranging the plurality of transfer extend entries into at least one thread in response to step (A);
(C) interrupting a processor of the peripheral device in response to starting a new thread of the at least one thread; and
(D) interrupting the processor in response to completing the new thread.
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Accused Products
Abstract
The present invention includes a Command Queuing Engine (CQE) that is a firmware-assist block which processes some of the firmware tasks related to command and context management preferably for SCSI. When enabled, CQE will decode SCSI commands as they arrive, and determine if DMA contexts can be automatically configured and started to transfer the data for those commands. CQE can also program DMA contexts to automatically return status information either after the disk has completed a transfer (as in non-cached writes) or after the DMA transfer is completed (as in reads or cached writes). CQE also utilizes a buffer-based linked-list to queue the SCSI commands as they arrive for future DMA context configuration. The present invention provides automated recognition and linking of commands belonging to a common thread, i.e., are sequential. The present invention also provides extensive thread boundary information and flexible firmware control for reordering commands. Automatic TE entry generation and storage to buffer memory, and automatic TE retrieval from the buffer memory and execution of entire command threads are further features provided by the present invention. As a result, bus command response latency is decreased by reducing the delay for the command to be started and at the end of the data transfer for status to be send. Disk efficiency is increased by reducing the latency to back-fill or empty a buffer memory segment of data that will be transferred. Furthermore, the present invention is a low-cost trade-off between hardware and firmware functionality.
74 Citations
17 Claims
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1. A method of data transfer between a peripheral device and a host computer, the method comprising the steps of:
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(A) generating a plurality of transfer extend entries in the peripheral device in response to a plurality of commands received from the host computer;
(B) arranging the plurality of transfer extend entries into at least one thread in response to step (A);
(C) interrupting a processor of the peripheral device in response to starting a new thread of the at least one thread; and
(D) interrupting the processor in response to completing the new thread. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A data controller of a peripheral device in communication with a host computer, the data controller comprising:
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a processor; and
a transfer extend generator configured to (i) generate a plurality of transfer extend entries in response to a plurality of commands received from the host computer, (ii) arrange the plurality of transfer extend entries into at least one thread, (iii) interrupt the processor in response to starting a new thread of the at least one thread, and (iv) interrupt the processor in response to completing the new thread. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A peripheral device to a host computer, the peripheral device comprising:
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means for generating a plurality of transfer extend entries in response to a plurality of commands received from the host computer;
means for arranging the plurality of transfer extend entries into at least one thread in response to generating;
means for interrupting a processor of the peripheral device in response to starting a new thread of the at least one thread; and
means interrupting the processor in response to completing the new thread.
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Specification