A request processing method for a 3d MLC flash memory device

Abstract

The invention discloses a request processing method of a 3D MLC flash memory device, which includes: executing a read request in a manner of prioritizing the read request; executing a write request when the wafer is idle; and ensuring that the wafer to which the read / write request is executed The working mode is consistent with the working mode of the block to which it belongs; the garbage collection request is executed when the wafer is free, and when the current capacity of the device is not sufficient, the block with the least effective pages among the blocks in SLC mode is selected as the block to be recycled, and the block in the current queue of the device When congestion occurs, select the free block in SLC mode as the target block, and when the current capacity of the device is not sufficient, set the working mode of the erased block to be recovered to MLC mode; if the total number of erasing times of all wafers increases by a certain amount , then cyclically set the working mode of the next wafer to SLC mode. The invention can make full use of the new characteristics of the 3D MLC flash memory chip, reduce the time delay of garbage collection, and improve the service life of the flash memory device.

Description

technical field [0001] The invention belongs to the field of SSD (Solid State Disk, solid state disk, solid state disk for short) storage control, and more specifically relates to a request processing method of a 3D MLC flash memory device. Background technique [0002] Due to its advantages in performance and energy consumption, flash memory is widely used in scenarios such as personal computers, servers, and data centers. However, NAND flash memory has reached its physical limit when the process is less than 20nm, and many flash memory manufacturers have shifted their development focus to 3D flash memory. Compared with 2D flash memory, 3D flash memory has higher density and lower price. 3D flash memory chips also provide more advanced command support. First of all, the 3D flash memory chip can interrupt the writing operation or erasing operation being performed on the chip, and resume the previous writing operation or erasing operation after performing other operations. ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the defects and improvement needs of the prior art, the present invention provides a request processing method for a 3D MLC flash memory device, the purpose of which is to make full use of the 3D MLC flash memory chip, which can interrupt the write / erase operation and dynamically adjust the internal memory of the wafer through advanced commands. The characteristics of the working mode of the flash memory block reduce the delay of garbage collection, so as to alleviate the performance degradation caused by the long garbage collection delay of 3D MLC applied in the solid state disk system, and reduce the number of times of erasing of the flash memory device, thereby Extend the life of your SSD

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