The FFS3 filesystem drivers support one or more logical flash drives. Each logical drive is called a socket, which consists of a contiguous and homogeneous region of flash memory. For example, in a system containing two different types of flash device at different addresses, where one flash device is used for the boot image and the other for the flash filesystem, each flash device would appear in a different socket.
Each socket may be divided into one or more partitions. Two types of partitions are supported: raw partitions and flash filesystem partitions.