A design method of a page-level flash memory conversion layer of a solid-state hard disk

[0083] Embodiment 1: The write request does not hit in W-CMT and R-CMT.

[0084] Suppose the initial state of the mapped buffer is as Figure 5 As shown in the "initial state" in the figure, there is a request "access data page LPN=1280, write access request, request size 1" arrives, and the processing process is as follows:

[0085] C1, when an access request arrives (LPN=1280), first query the W-CMT, and the request mapping item is not found in the W-CMT, and then query in the R-CMT, and the request mapping item is also not found. At this point, the mapping information of the access request needs to be loaded into the W-CMT.

[0086] C2. At this time, the W-CMT is in a full state, and a mapping item needs to be selected for removal. Since there is no clean mapping information in the priority replacement area, the mapping information (LPN=6) at the LRU position is selected as the victim item (ie, the item to be eliminated).

[0087] C3, through the LPN of the victim item, cal

[0096] Embodiment 2: The write request hits in the R-CMT.

[0097] Suppose the initial state of the mapped buffer is as Figure 6 As shown in the "initial state" in "Initial State", there is an existing "access data page LPN=1280, write access request, request size is 1" request arrives, and its processing process is as follows: C1, when an access request arrives (LPN= 1280), query W-CMT first, no request mapping item is found in W-CMT,

[0098] C2 then inquires in the R-CMT, and finds the mapping information corresponding to the request in the R-CMT.

[0099] C3, W-CMT is full at this time, query whether there is a clean mapping item in the priority replacement area, and get a clean mapping item of LPN=833, then remove it as a victim item.

[0100] C4, and then migrate the mapping information from the R-CMT to the MRU position of the W-CMT.

[0101] C5, assuming that the newly allocated data page of the flash memory is PPN=661, update the mapping information, and set the upda

[0103] Embodiment 3: The write request hits in the W-CMT.

[0104] Suppose the initial state of the mapped buffer is as Figure 7 As shown in the "initial state" in the figure, there is a request "access data page LPN=1280, write access request, request size 1" arrives, and the processing process is as follows:

[0105] C1, when an access request arrives (LPN=1280), first query the W-CMT, and query the request mapping information in the W-CMT.

[0106] C2. Migrate the mapping information to the MRU position of the W-CMT.

[0107] C3, assuming that the newly allocated data page of the flash memory is PPN=661, update the mapping information, and set the update bit to dirty (Update_flag=1).

[0108] To sum up, the status of the mapping buffer after processing is as follows Figure 7 shown in "End State".