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Undid revision 1286720581 by 76.91.82.108 (talk) since it was a rather random and mid-sentence delete. |
→Factors affecting the value: Clarified that dropping ANY multiple-bit cell to a lower value helps. Tags: Mobile edit Mobile web edit |
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| Using [[Multi-level cell
| This writes data at a rate of one bit per cell instead of the designed number of bits per cell (normally two bits per cell or three bits per cell) to speed up reads and writes. If capacity limits of the NAND in SLC mode are approached, the SSD must rewrite the oldest data written in SLC mode into MLC / TLC mode to allow space in the SLC mode NAND to be erased in order to accept more data. However, this approach can reduce wear by keeping frequently-changed pages in SLC mode to avoid programming these changes in MLC / TLC mode, because writing in MLC / TLC mode does more damage to the flash than writing in SLC mode.{{cn|date=January 2021}} Therefore, this approach drives up write amplification but could reduce wear when writing patterns target frequently-written pages. However, sequential- and random-write patterns will aggravate the damage because there are no or few frequently-written pages that could be contained in the SLC area, forcing old data to need to be constantly be rewritten to MLC / TLC from the SLC area. This method is sometimes called "SLC cache" or "SLC buffer". It has two types of "SLC buffer"; one type is static SLC buffer (a SLC buffer based on the over-provisioning area), another type is dynamic SLC buffer (dynamically change its size on factors such as free user capacity).
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