What are the functions of SDRAM FLASH NVRAM CFCARD on a board

Hi, Qazike.
As far as I'm concerned:
SDRAM: It is generally used as the external memory of the processor. After the board is started, the task runs on the SDRAM, which can be considered as the memory bar of the PC.
FLASH: Data will not be lost after power-off. For some boards, if a small amount of data needs to be stored, only the flash memory is required. The CF card is not required. The CF card is mainly used to store the system software package, configuration, logs, and diagnostic information.
CFCARD: Data will not be lost after a power failure. The MPU has a large storage capacity. It can store system software packages, configurations, and logs.
NVRAM: Non-volatile random access memory. Unlike traditional hard disks, the non-volatile random access memory provides random read and write functions. It is usually used on a board in special scenarios, such as recording the last words. When the board is restarted or powered off, the onsite running information can be saved in a timely manner to facilitate subsequent fault locating.

Thank you!