A method for implementing a flash conversion layer of a solid state disk

Abstract

The invention discloses an implementation method for a flash translation layer of a solid-state disc. The implementation method includes that a read-write request sent by a file system is received and corresponds to a page with a logic address K; whether the logic address K is targeted in a cache mapping table is judged; if the logic address K is not targeted in the cache mapping table, whether the number (n) of mapping relations to be transferred to the cache mapping table for one time can be contained in the cache mapping table is judged; if the number (n) of mapping relations cannot be contained in the cache mapping table, a logic page number Victim_Num of a mapping relation which is used the least recently is found out in the cache mapping table, all logic page numbers stored in the same page as the mapping relation of the Victim_Num are found in the cache mapping table, and n mapping relations used the least recently are found from mapping relations corresponding to the logic page numbers; and then corresponding mapping relations are found in a global conversion directory according to the Victim_Num. The implementation method for the flash translation layer of the solid-state disc is higher in read-write efficiency, improves performance of the system, and prolongs the service life of the solid-state disc.

Description

technical field [0001] The invention belongs to the technical field of solid-state disk storage, and more particularly relates to a method for realizing a flash conversion layer of a solid-state disk. Background technique [0002] In recent years, flash memory (Flash) technology has led new changes in the storage field. With its small size, fast speed, low power consumption, no noise and anti-vibration and many other advantages, it has gradually replaced the traditional mechanical hard disk. [0003] It is completely different from traditional hard disks, such as figure 1 As shown, the flash memory chip (FlashChip) 101 in the prior art is made up of a plurality of blocks (Block) 102, and a block 102 is made up of a plurality of pages (Page) 103, usually 64, and one page 103 is divided into two There are three areas, which are respectively composed of data area 104 (DataArea) and OOB area (Out-ofBandarea) 105. Generally, the data area in a page 103 is 512B, and the OOB is ...

AI Technical Summary

Problems solved by technology

[0007] In the existing FTL, although the feature of erasing before writing can be shielded from the upper system, there are still obvious deficiencies: 1. The cache scheduling algorithm in it is not well combined with the read and write characteristics of the solid state disk; For example, the commonly used page-level mapping FTL now uses the LRU algorithm commonly used in the traditional file system used in the transfer of the mapping relationship to the cache, that is, only one mapping relationship is transferred at a time, but the SSD uses pages as read and write units. Calling in a mapping relationship requires reading the entire mapping page, calling out and updating a mapping relationship requires writing the entire mapping page

Therefore, the hit rate of the existing FTL call-out algorithm applied to the solid-state disk is not ideal.

However, the SSD cache miss overhead is very high (if the mapping needs to be updated, the miss overhead includes two read operations and one write operation), which seriously reduces the life of the hard disk.

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