Unlike the desktop version of Python, MicroPython is a stripped-down version for microcontrollers; therefore it does not support all Python libraries and functionalities. In the world of microcontrollers, the firmware is directly burned to the ROM (also known as program memory), and there is no file system. MicroPython implements a minimal type of file system directly on the flash memory of the microcontrollers. If the device has 1MB or more of storage, then it will be set up (upon first boot) to contain a file system. This file system uses FAT format and is stored in the flash memory by MicroPython firmware. This gives you the benefit of being able to access, read and write files within the main Python program for flexible storage operations.