For file systems not designed for flash, FTL layer conversion is required.

Flash memory is divided into two types: nor flash memory and nand flash memory, especially for NAND Flash
Memory features faster erase time, small size, and low cost, making NAND more suitable
Embedded system. Flash memory is a storage device. To use this storage device
Use File System on memory. The file system used on a general block device (e.g. Disk), for example:
NTFS, FAT32, and ext2 can be used on flash memory, but these file systems are not designed for flash
Designed, so there is no operation for flash features, because some need to use FTL (Flash Translation Layer)
Shows the conversion operation:

Figure 1
If you use a file system (flash-specific File System) not designed for flash
In other words, you can access flash memory. However, if you use FTL, there will be an additional conversion process, which will waste the conversion time.
Embedded system, which requires high efficiency, is not suitable for flash memory.
(Flash-specific File System) file system, such as jffs, jffs2, and yaffs. Use this
Flash-specific file system does not need to use FTL for conversion, as shown in Figure 2:

Figure 2
Jffs is mainly used on nor flash memory, while yaffs is used on nand flash memory. Yaffs
It is made by Aleph one and is suitable for many embedded operation systems, such as eCos and wince.
And open the original code under the terms of gnu gpl. Therefore, you can obtain the yaffs from Aleph one.
And can be modified to meet your needs. Here we will mainly discuss the use of nand flash memory
Flash-specific file system-yaffs.