If we meet sudden power off, Solid State Drive will face below 3 questions while computer using:
1.The mapping table can not update and save data timely, causing the mapping table lost. The general SSD manufacturer does not provide any tools for users to restore the mapping table. Therefore, once the mapping table is lost, the solid state disk cannot be recognized by the system. It can only be repaired by returning to the factory. Generally, after returning to the factory, maintenance is performed by reopening the card for mass production, which will cause all user data to be lost.
2.Solid state hard disks generally use SDRAM or DDR as a cache. DDR is a volatile storage medium. Once the power is turned off, all data in DDR is lost. The writing command issued by the host is because the data has been written to the solid state hard disk DDR. The instruction to complete the writing, because the writing speed of DDR and NAND Flash are very different. If the data in DDR has not been completely written into NAND Flash, abnormal power failure will lead data loss which have not been written into NAND Flash.
3. Sudden power off also will gain bad block. SSD controller ECC function will handle 256 bit data, include Contains column and row checks, if pending bits are different, then result is zero, then it means even 1. if the result is 1, then it means odd number 1. But ECC can not be corrected over ability, so, while sudden power off over 1 bit data error, controller will judge “bad block” wrong, normal hard drive software can check new bad block gain after sudden power off.