mtd-utils ========= This package provides userspace utilities for working with Linux MTD and UBI infrastructure, as well as related filesystems (JFFS2, UBIFS). MTD stands for "Memory Technology Devices" and means flash, RAM and similar chips, used for solid state storage on embedded devices. Think of e.g. a raw nand-flash chip attached directly to an SoC via parallel or SPI bus, but without _any_ special management like an eMMC has. The MTD subsystem exposes those devices to userspace as character devices. It provides a unified interface, but does not attempt to hide the page vs erase-block device geometry or issues involved in dealing with the underlying storage, like wear or bad blocks. For this purpose, UBI provides a layer on top of MTD that hides away some of those complexities. UBI also implements LVM-like logical volume partitioning and some other useful capabilities. UBI does not emulate block device like storage. UBI volumes are exposed as character devices with page vs erase-block access geometry, much like MTD partitions. But they behave more like a flash chip with "idealized" properties and transparent wear-leveling. JFFS2 is a flash friendly filesystem. It predates UBI and is designed to run on top of raw MTD, implementing its own wear leveling. The more recent UBIFS (formerly JFFS3) can be used on top of UBI volumes and offers a number of improvements over JFFS2, offers newer compression schemes and advanced features like file-level encryption and authentication. Installing ---------- mtd-utils are packaged by a number of Linux distributions[0] and can be installed via the package management system. A Yocto recipe is available as well[1] as part of the openembedded-core layer. Should the tools be too big for on-device use, the BusyBox project provides compatible clone versions. Before making this choice however, please note that some "heavy weight" tools like mkfs.ubifs are typically not needed on the device itself. The kernel module can format a volume on first mount. Other, heavy weight tools like lsmtd can be disabled via a configure flag. [0] https://repology.org/project/mtd-utils/versions [1] https://layers.openembedded.org/layerindex/recipe/262/ How to get the source --------------------- The official git repository and release tarballs are hosted on infradead.org: Relase tarballs: ftp://ftp.infradead.org/pub/mtd-utils git repository: git://git.infradead.org/mtd-utils.git This is also where the website and documentation are hosted: http://www.linux-mtd.infradead.org/ A http mirror is also provided on infraroot.at: Relase tarballs: https://infraroot.at/pub/mtd git repository: https://git.infraroot.at/mtd-utils.git There are a number of mirrored repositories on GitHub, but this is not where official development takes place. If you want to contribute upstream, please do not open any issues or pull requests there. Upstream development is done via mailing list (see below). How to build ------------ mtd-utils uses an autotools based build system. If you are building the git tree, you first need to run `./autogen.sh`. This sets up the build system and requires autoconf, automake and possibly other autotools to be installed. After unpacking a tarball (or running autogen.sh) simply run: $ ./configure $ make to build the package. This does not require autotools to be installed, but does need pkg-config, make, etc... There are a number of configure switches to tune the build. Run `./configure --help` to get an overview. For compiling mtd-utils, you need development packages for the following dependency libraries: zlib (required by mkfs.ubifs, mkfs.jffs2 lzo2 (optional dependency for mkfs.ubifs, mkfs.jffs2) zstd (optional dependency for mkfs.ubifs) libuuid* (required by mkfs.ubifs) libselinux (optional dependency for mkfs.ubifs) openssl (optional dependency for mkfs.ubifs) * this library is part of util-linux, aka util-linux-ng and some distributions package it under that name. If you don't explicitly disable xattr support, mkfs.ubifs and mkfs.jffs2 require the "sys/xattr.h" and "sys/acl.h" header files, depending on your Distributions, those may be packaged as part of libattr and libacl respectively. Please note that the mkfs tools are optional and can be disabled via a configure flag. This should also remove the need for the dependency libraries. How to contribute ----------------- Development of mtd-utils takes place on the linux-mtd mailing list: mailto: linux-mtd@lists.infradead.org archive: https://lists.infradead.org/pipermail/linux-mtd/ You can subscribe here: http://lists.infradead.org/mailman/listinfo/linux-mtd/ or simply send "subscribe" to linux-mtd-request@lists.infradead.org Contributions are submitted in the form of plain text patches, using `git send-email` or similar. Please prefix your subject with "mtd-utils: " to make them easier to spot. It may take a few days for a patch to be picked up. This is in part done intentionally to allow other people to comment on it. If it's been more than a week and you feel your patch might have been overlooked, please send a friendly ping, or re-submit the patch series with "[RESEND]" in the subject. There is also a #mtd IRC channel on irc.oftc.net