this is just a quick tip, you know since the usb flash disk have grown in size, so it is able to hold a very large data.
Now the default format for the flash disk is fat32, normally you cannot change that. exfat also available but the format is not widely supported because of the need of licensing.
Now since the growing of the size, the fat format becomes a problem, because it cannot hold a single large file (must have below 4gb file size), you must split the file into not so big sized files. extfat can accept large data but again it is not widely supported by devices, and it is slower than fat32.