Adaptive copy-back method and storage device using same
AssigneeSamsung Electronics Co., Ltd.
InventorsHYUN-UK JUNG, DONG-GIL LEE, JIN-YEONG KIM
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Abstract
During a garbage collection process for a non-volatile memory device of a storage device, an adaptive copy-back method selectively performs either an external or an internal copy-back operation in view of certain performance conditions for a storage device. The external copy-back operation is performed when a number of error-corrected bits per unit size of read data exceeds a given threshold value, and the internal copy-back operation is performed when the number of error-corrected bits does not exceed the threshold value.
Claims20
An adaptive copy-back method comprising:
- reading data from a source page of a non-volatile memory device and storing the data in a page buffer with the non-volatile memory device;
- performing error correction on the data stored in the page buffer according to a given unit size using error correction code (ECC) to determine a number of error-corrected bits and to generate error-corrected data;
- storing the error-corrected data in a buffer memory external to the non-volatile memory device;
- and
- selectively performing either an external copy-back operation using the error-corrected stored in the buffer memory, or an internal copy-back operation using the data stored in the page buffer in accordance with the number of error-corrected bits.
An adaptive copy-back method comprising:
- determining whether a performance reduction condition occurs due to a bottleneck phenomenon related to input/output (1/0) accesses to a buffer memory of a storage device;
- selecting a first copy-back operation if the performance reduction condition occurs and selecting a second copy-back operation if the performance reduction condition does not occur, wherein upon selecting the first copy-back operation, data stored in a page buffer of a memory device is programmed in a target page of the memory device without accessing data stored in the buffer memory when a number of error-corrected bits per unit size of the data read from a source page to the page buffer is less than a threshold value, and
- upon selecting the second copy-back operation, reading error-corrected data stored in the buffer memory and programming the error-corrected data in the target page of the memory device.
A storage device comprising:
- a non-volatile memory device comprising a page buffer that temporarily stores data read from at least one source page;
- a buffer memory external to the non-volatile memory device;
- and
- a memory controller that performs error correction on the data provided from the page buffer to generate error-corrected data and determine a number of error-correct bits per unit size of the data, stores the error-corrected data in the buffer memory, and then selectively performs, in view of the number of error-corrected bits per unit size of the data, one of an external copy-back operation using the error-corrected data stored in the buffer memory, and an internal copy-back operation using the data stored in the page buffer.
A method of operating a storage device including a non-volatile memory device having multiple non-volatile memory chips arranged in operation according to multiple channels and a volatile buffer memory, the method comprising:
- during a garbage collection process for the non-volatile memory device, determining whether a performance reduction condition exists by determining a number of the multiple channels accessing the buffer memory;
- and
- upon determining that the performance reduction condition exists, performing at least one copy-back operation,
- wherein the at least one copy-back operation is an external copy-back operation that transfers data stored in the buffer memory to the non-volatile memory when a number of error-corrected bits per unit size for data stored in a page buffer of the non-volatile memory device exceeds a threshold value, or
- the at least one copy-back operation is an internal copy-back operation that does not transfer data stored in the buffer memory to the non-volatile memory when the number of error-corrected bits per unit size for the data stored in the page buffer does not exceed the threshold value.
Dependencies are inferred from the claim text.