4UBIFS file-system stands for UBI File System. UBI stands for
"Unsorted    5Block Images". UBIFS is a flash file system, which
means it is designed    6to work with flash devices. It is
important to understand, that UBIFS    7is completely different
to any traditional file-system in Linux, like    8Ext2, XFS,
JFS, etc. UBIFS represents a separate class of file-systems
9which work with MTD devices, not block devices. The other Linux
10file-system of this class is JFFS2.   12To make it more clear,
here is a small comparison of MTD devices and   13block devices.
151 MTD devices represent flash devices and they consist of
eraseblocks of   16  rather large size, typically about 128KiB.
Block devices consist of   17  small blocks, typically 512
bytes.   182 MTD devices support 3 main operations - read from
some offset within an   19  eraseblock, write to some offset
within an eraseblock, and erase a whole   20  eraseblock. Block
devices support 2 main operations - read a whole   21  block and
write a whole