Hi Praveen,
These are the filesystem types supported by booted kernel uImage.
sysfs - used to check & change system driver info
procfs - used to check processor info
vfat - windows based filesystem format like FAT
1) Format your pendrive in windows then do the following command.
mount -t vfat /dev/sdb1 /mnt
2) You cannot mount your NAND in "jffs2" fs fomat since support is not enabled in your booted kernel image.
3) Instead you can see & try the "ubifs" fs support for NAND flash.
4) If you want to mount your NAND flash in jffs2fs format then enable jffs2support in linux kernel configuration.