How to Fix SD Card Reader Not Working?

Actually, comparing with SSD which also uses flash memory as storage media, SD card is much easier to get damaged. Because most SD card will not take the wear leveling technology to extend the lifespan of flash memory to get a low production cost, this will lead to the first several flash memory fail to read the data inside and even lost the data. Besides, the flash memory that used in the SD card is the low-cost one and the lifespan of such flash memory is not guaranteed.

What is Wear Leveling
The NAND flash memory has limited number of erase cycles which will be based on the manufacturing technology. And repeated writing and erasing of the same block will lower the data transmission speed and even damage the block. Wear Leveling will balance the usage of the blocks in NAND flash memory, which will help to avoid the data being written or assessed in the same block and extend the lifespan of the storage devices.

Wear Leveling will work around the erase cycles by arranging the written data to different blocks so that to avoid specific block exceeding its erase endurance. Wear Leveling should get each of the blocks to reach its erase endurance and extend the lifespan of the flash device. In other words, Wear Leveling is designed to equalize the use of each block in the flash memory and prevent single block from wearing out or data lost. And Wear leveling could be divided into 3 different modes:

Dynamic Wear Leveling: Uses the available blocks that are free of data and select the block with the lowest erase count for the next write

Static Wear Leveling: Utilizes all good blocks to evenly distribute wear throughout the entire device. And the static data will be moved to blocks with higher erase counts while the blocks with low erase count will be included in the next write cycles.

Global Wear Leveling: Utilizes all flash memory in the storage devices and will evenly save data to blocks with low erase count.

As we can see, for SD card which does not have Wear Leveling, the beginning blocks of the flash memory will easily reach its erase cycles and get damaged. As a result, the file system of the SD card will get damaged and the SD card will fail to read or write data. Also, data inside the SD card will lost.

When we encounter data lost because of the damaged SD card, it is recommended to try the professional data recovery software – Renee Undeleter to recover data from the damaged SD card. It can help you rebuild the file system for the SD card by skipping the damaged blocks and recover the lost data from the SD card.