Storage manufacturers are getting ready to start shipping solid state disks, and Linux-based devices like One Laptop per Child's XO and Intel's Classmate don't contain standard hard disks. To improve performance on the wide array of flash memory storage devices now available, project leader Jörn Engel has announced LogFS, a scalable filesystem specifically for flash devices. Linux users already have two mature flash filesystems to choose from -- JFFS2 and YAFFS -- so why do they need another?