Yaffs (Yet Another Flash File System) is a file system designed and written by Charles Manning for the company Aleph One. Yaffs1 was the first version of this file system and was designed for the then-current NAND chips with 512 byte page size (+ 16 byte spare (OOB;Out-Of-Band) area). Work started in 2002, and it was first released later that year. The initial work was sponsored by Toby Churchill Ltd, and Brightstar Engineering. Designing a storage system that enforces a "write once rule" ("write once property") has several advantages.