Hi @mastupristi ,
Thanks for your interest in NXP MIMXRT series!
In the RT series SDK, the fsl_usb_disk is the abstraction layer in the FatFs file system for USB storage devices. Instead of being stored in RAM, the file system is stored on an external storage device connected via USB, such as a USB flash drive or hard disk. When you use `fsl_usb_disk`, it manages the file system on the USB storage device.
Best regards,
Gavin