documentation/overview-manual/yp-intro.rst

1 .. SPDX-License-Identifier: CC-BY-SA-2.0-UK
11 developers create custom Linux-based systems that are designed for
26 .. image:: figures/key-dev-elements.png
31 …ticle <https://www.embedded.com/electronics-blogs/say-what-/4458600/Why-the-Yocto-Project-for-my-I…
39 --------
43 -  *Widely Adopted Across the Industry:* Many semiconductor, operating
50 -  *Architecture Agnostic:* Yocto Project supports Intel, ARM, MIPS,
55    Aside from broad architecture support, the Yocto Project fully
59 -  *Images and Code Transfer Easily:* Yocto Project output can easily
68 -  *Flexibility:* Corporations use the Yocto Project many different
75 -  *Ideal for Constrained Embedded and IoT devices:* Unlike a full Linux
85 -  *Comprehensive Toolchain Capabilities:* Toolchains for supported
89    platform-specific tuning parameters. And, should you need to use a
90    third-party toolchain, mechanisms built into the Yocto Project allow
93 -  *Mechanism Rules Over Policy:* Focusing on mechanism rather than
98 -  *Uses a Layer Model:* The Yocto Project :ref:`layer
99    infrastructure <overview-manual/yp-intro:the yocto project layer model>`
106 -  *Supports Partial Builds:* You can build and rebuild individual
108    :ref:`overview-manual/concepts:shared state cache` (sstate) scheme.
112 -  *Releases According to a Strict Schedule:* Major releases occur on a
113    :doc:`six-month cycle </ref-manual/release-process>`
119 -  *Rich Ecosystem of Individuals and Organizations:* For open source
124 -  *Binary Reproducibility:* The Yocto Project allows you to be very
126    binary reproducibility (e.g. 99.8% for ``core-image-minimal``). When
131 -  *License Manifest:* The Yocto Project provides a :ref:`license
132 …manifest <dev-manual/common-tasks:maintaining open source license compliance during your product's…
137 ----------
141 -  *Steep Learning Curve:* The Yocto Project has a steep learning curve
145 -  *Understanding What Changes You Need to Make For Your Design Requires
150 …it for your project, see the ":ref:`what-i-wish-id-known:what i wish i'd known about yocto project…
151 …":ref:`transitioning-to-a-custom-environment:transitioning to a custom environment for systems dev…
154 -  *Project Workflow Could Be Confusing:* The :ref:`Yocto Project
155    workflow <overview-manual/development-environment:the yocto project development environment>`
159    and install new packages, which are typically pre-compiled binaries
164 -  *Working in a Cross-Build Environment Can Feel Unfamiliar:* When
181 -  *Initial Build Times Can be Significant:* Long initial build times
183    initially built from scratch for a fully functioning Linux system.
184    Once that initial build is completed, however, the shared-state
217    -  Use Board Support Package (BSP) layers from silicon vendors when
220    -  Familiarize yourself with the
221       :yocto_home:`Yocto Project curated layer index</software-overview/layers/>`
226    -  Layers support the inclusion of technologies, hardware components,
228       Compatible <dev-manual/common-tasks:making sure your layer is compatible with yocto project>`
232       OE-compatible layers, and related open-source projects, allowing
242 understand, however, that the BSP layer can still make machine-specific
244 the GUI layer itself with those machine-specific changes. You can
251    :doc:`/bsp-guide/index`.
257 with the string ``meta-``.
262    ``meta-``, but it is a commonly accepted standard in the Yocto Project
267 ``meta-skeleton``, ``meta-selftest``, ``meta-poky``, and
268 ``meta-yocto-bsp``. Each of these repositories represents a distinct
272 ":ref:`dev-manual/common-tasks:understanding and creating layers`"
289 -----------------
294 -  *CROPS:* `CROPS <https://github.com/crops/poky-container/>`__ is an
295    open source, cross-platform development framework that leverages
301 -  *devtool:* This command-line tool is available as part of the
307    The ``devtool`` command employs a number of sub-commands that allow
324    ":ref:`sdk-manual/extensible:using \`\`devtool\`\` in your sdk workflow`"
327 -  *Extensible Software Development Kit (eSDK):* The eSDK provides a
328    cross-development toolchain and libraries tailored to the contents of
336    For information on the eSDK, see the :doc:`/sdk-manual/index` Manual.
338 -  *Toaster:* Toaster is a web interface to the Yocto Project
341    :doc:`/toaster-manual/index`.
344 ----------------
349 -  *Auto Upgrade Helper:* This utility when used in conjunction with the
352    OE-Core) automatically generates upgrades for recipes that are based
354    :ref:`dev-manual/common-tasks:using the auto upgrade helper (auh)`
357 -  *Recipe Reporting System:* The Recipe Reporting System tracks recipe
362    is a website that indexes OpenEmbedded-Core layers.
364 -  *Patchwork:* `Patchwork <https://patchwork.yoctoproject.org/>`__
366    `OzLabs <https://ozlabs.org/>`__. The project is a web-based tracking
372 -  *AutoBuilder:* AutoBuilder is a project that automates build tests
388    Autobuilder :doc:`here </test-manual/understand-autobuilder>`.
390 -  *Pseudo:* Pseudo is the Yocto Project implementation of
405    ":ref:`overview-manual/concepts:fakeroot and pseudo`" section.
407 Open-Embedded Build System Components
408 -------------------------------------
412 -  *BitBake:* BitBake is a core component of the Yocto Project and is
419    within complex inter-task dependency constraints. In short, BitBake
426 -  *OpenEmbedded-Core:* OpenEmbedded-Core (OE-Core) is a common layer of
428    OpenEmbedded-derived systems, which includes the Yocto Project. The
430    OpenEmbedded-Core. You can find the OE-Core metadata in the Yocto
433    Historically, the Yocto Project integrated the OE-Core metadata
437    metadata (OE-Core), which contained much of the functionality
438    previously found in Poky. This collaboration achieved a long-standing
440    quality-assured core. The results also fit well with the Yocto
441    Project objective of achieving a smaller number of fully featured
445    layer on top of OE-Core. You can see that in this
446    :ref:`figure <overview-manual/yp-intro:what is the yocto project?>`.
447    The Yocto Project combines various components such as BitBake, OE-Core,
451 -----------------------------
455 (BitBake and OE-Core) as well as a set of metadata to get you started
457 ":ref:`overview-manual/yp-intro:what is the yocto project?`"
470 ":ref:`overview-manual/yp-intro:reference embedded distribution (poky)`"
474 -----------------------------
478 -  *Matchbox:* Matchbox is an Open Source, base environment for the X
479    Window System running on non-desktop, embedded platforms such as
480    handhelds, set-top boxes, kiosks, and anything else for which screen
484    applications that you can tailor to a specific, non-desktop platform
490 -  *Opkg:* Open PacKaGe management (opkg) is a lightweight package
510 -------------------
514 non-Linux development system.
522    GUI-based interface to the Yocto Project. Toaster has fully replaced
527    day-to-day production development environment with the Yocto Project.
533    :ref:`CROPS <overview-manual/yp-intro:development tools>`.
552    environment, see the ":doc:`/overview-manual/development-environment`"
555 -  *Native Linux Host:* By far the best option for a Build Host. A
564    ":ref:`dev-manual/start:setting up a native linux host`"
567 -  *CROss PlatformS (CROPS):* Typically, you use
568    `CROPS <https://github.com/crops/poky-container/>`__, which leverages
574       You can, however, use CROPS on a Linux-based system.
576    CROPS is an open source, cross-platform development framework that
584    ":ref:`dev-manual/start:setting up to use cross platforms (crops)`"
587 -  *Windows Subsystem For Linux (WSLv2):* You may use Windows Subsystem
600    ":ref:`dev-manual/start:setting up to use windows subsystem for linux (wslv2)`"
603 -  *Toaster:* Regardless of what your Build Host is running, you can use
611    :doc:`/toaster-manual/index`.
616 "Poky", which is pronounced *Pock*-ee, is the name of the Yocto
619 :term:`OpenEmbedded-Core (OE-Core)`) as well as a set of
625 Poky is a combined repository of BitBake, OpenEmbedded-Core (which is
626 found in ``meta``), ``meta-poky``, ``meta-yocto-bsp``, and documentation
635    Git repository, see the ":ref:`ref-manual/structure:top-level core components`"
640 .. image:: figures/poky-reference-distribution.png
643 -  BitBake is a task executor and scheduler that is the heart of the
646 -  ``meta-poky``, which is Poky-specific metadata.
648 -  ``meta-yocto-bsp``, which are Yocto Project-specific Board Support
651 -  OpenEmbedded-Core (OE-Core) metadata, which includes shared
657 -  Documentation, which contains the Yocto Project source files used to
675 Poky has a regular, well established, six-month release cycle under its
679 cadence, see the ":doc:`/ref-manual/release-process`" chapter in the
684 of the box to create an image ranging from a shell-accessible minimal
685 image all the way up to a Linux Standard Base-compliant image that uses
692 `layers <overview-manual/yp-intro:the yocto project layer model>` that extend
699 A recipe is a collection of non-executable metadata used by BitBake to
700 set variables or define additional build-time tasks. A recipe contains
705 defined by the classes it inherits from the OE-Core layer's class
712 ":ref:`bitbake:bitbake-user-manual/bitbake-user-manual-metadata:appending and prepending (override …
722 .. image:: figures/YP-flow-diagram.png
751 ":ref:`overview-manual/concepts:openembedded build system concepts`" section.
758 Terms </ref-manual/terms>`" section of the Yocto Project
762 -  *Configuration Files:* Files that hold global definitions of
763    variables, user-defined variables, and hardware configuration
768 -  *Extensible Software Development Kit (eSDK):* A custom SDK for
772    on the eSDK, see the :doc:`/sdk-manual/index` manual.
774 -  *Layer:* A collection of related recipes. Layers allow you to
784    ":ref:`dev-manual/common-tasks:understanding and creating layers`"
787    ":ref:`bsp-guide/bsp:bsp layers`" section in the Yocto
790 -  *Metadata:* A key element of the Yocto Project is the Metadata that
800    the software for use in a particular situation. OpenEmbedded-Core is
803 -  *OpenEmbedded Build System:* The terms "BitBake" and "build system"
814    performs a native or cross-compilation of each package. As a first
815    step in a cross-build setup, the framework attempts to create a
816    cross-compiler toolchain (i.e. Extensible SDK) suited for the target
819 -  *OpenEmbedded-Core (OE-Core):* OE-Core is metadata comprised of
821    be common among many different OpenEmbedded-derived systems,
822    including the Yocto Project. OE-Core is a curated subset of an
825    recipes. The result is a tightly controlled and quality-assured core
831 -  *Packages:* In the context of the Yocto Project, this term refers to
839    ":ref:`ref-manual/system-requirements:required packages for the build host`"
845    Project, recipes were referred to as packages - thus, the existence
846    of several BitBake variables that are seemingly mis-named, (e.g.
851 -  *Poky:* Poky is a reference embedded distribution and a reference
854    -  A base-level functional distro used to illustrate how to customize
857    -  A means by which to test the Yocto Project components (i.e. Poky
860    -  A vehicle through which you can download the Yocto Project.
867       Poky is an integration layer on top of OE-Core.
869 -  *Recipe:* The most common form of metadata. A recipe contains a list