System and method for optimizing sequential XOR command performance
First Claim
Patent Images
1. A hard disk drive (HDD) comprising:
- at least one rotatable disk;
at least one data transfer element; and
at least one controller controlling the data transfer element to execute XOR commands by coalescing LBA-sequential XOR commands into pipes, and separately executing read commands and write commands in the pipes using skew information, each XOR command including at least one read followed by an XOR operation followed by at least one write of the result of the XOR operation, wherein optimal disk access lengths and optimal read/write switching points are determined based on skew information to minimize dead latency, and further wherein a read portion of an XOR command is terminated on a last skew boundary that allows just enough time to seek back to a starting location of the read portion to begin an XOR write operation without incurring an additional disk revolution.
2 Assignments
0 Petitions
Accused Products
Abstract
An RPO algorithm in a HDD coalesces LBA-sequential XOR commands in pipes, and passes the pipes to a lower level execution engine. The execution engine executes XOR reads and write separately to optimize performance using head and/or cylinder skew information to approach the nominal disk data rate.
10 Citations
13 Claims
-
1. A hard disk drive (HDD) comprising:
-
at least one rotatable disk; at least one data transfer element; and at least one controller controlling the data transfer element to execute XOR commands by coalescing LBA-sequential XOR commands into pipes, and separately executing read commands and write commands in the pipes using skew information, each XOR command including at least one read followed by an XOR operation followed by at least one write of the result of the XOR operation, wherein optimal disk access lengths and optimal read/write switching points are determined based on skew information to minimize dead latency, and further wherein a read portion of an XOR command is terminated on a last skew boundary that allows just enough time to seek back to a starting location of the read portion to begin an XOR write operation without incurring an additional disk revolution. - View Dependent Claims (2, 3, 4)
-
-
5. A controller executing logic comprising:
-
grouping multiple disk access commands in pipes, each command requiring at least one read along with at least one associated write; passing the pipes to an execution engine of a disk drive; separating multiple disk access command reads from corresponding writes and then executing the reads and writes based on skew, wherein optimal disk access lengths and optimal read/write switching points are determined based on skew to minimize dead latency, and further wherein a read portion of a command is terminated on a last skew boundary that allows just enough time to seek back to a starting location of the read portion to begin a related write operation. - View Dependent Claims (6, 7, 8)
-
-
9. A HDD comprising:
-
at least one disk; a controller writing data to and reading data from the disk in response to commands, each command requiring at least one read along with at least one associated write, the controller invoking; means for grouping LBA-sequential multiple disk access commands; means for separating reads from writes in the commands; and means for executing the reads and writes based on skew information, wherein optimal disk access lenghts and optimal read/write switching points are determined by the means for executing based on skew information to minimize dead latency, and wherein the means for executing terminates a read portion of an XOR command on a last skew boundary that allows just enough time to seek back to a starting location of the read portion to begin an XOR write operation without incurring an additional disk revolution. - View Dependent Claims (10, 11, 12, 13)
-
Specification