Origins of BitBake Naming

BitBake evolved out of OpenEmbedded in the early 2000s. The naming conventions reflect that history, and sometimes the variable names don’t line up exactly with what we call them today.

For example PN historically meant package name, but in today’s Yocto world it’s really the recipe name. The variable names are legacy but kept for compatibility across 20+ years of BitBake.

  • BitBake was originally modeled on make, but with a declarative, metadata-driven system.
  • In OpenEmbedded Classic, “package” was often used loosely to mean both the recipe (.bb) and the binary packages (.ipk, .deb, .rpm).

  • Over time, Yocto (2009–2011) standardized the terminology:

    • Recipe = the .bb file (instructions to build software).
    • Package = the binary outputs produced from recipes.

But many variable names (PN, PR, PV, etc.) were already established, so they stuck.

Key Variable Names and Their History

  • PN = Package Name

    • Original meaning: “the name of the package/recipe being built.”
    • Today, it’s effectively the recipe name (basename of the .bb file without version).
    • Example: zlib_1.2.11.bb → PN = "zlib".

  • PV = Package Version

    • Original meaning: “package version.”
    • Stuck around even though today it’s better thought of as the recipe version.
    • Comes directly from the filename: _1.2.11 → PV = "1.2.11".

  • PR = Package Revision

    • Originally for “incrementing package revisions” (like distro maintainers do in Debian/Fedora).
    • Default r0, incremented when you change the recipe but not the upstream version.
    • Still called “package revision” even though it applies to recipes.

  • P = Package (name+version)

    • Historical shorthand: ${PN}-${PV}.
    • Used for source tarball names like foo-1.2.tar.gz.

  • PF = Package Full

    • ${PN}-${PV}-${PR}.
    • Historical “full identifier of a package” in the old OE packaging days.
    • Today: the unique triplet of name/version/revision.

Recipe vs Package Today

  • Recipe = a .bb file (metadata). Identified by PN, PV, PR.

  • Package = one or more binary outputs (.deb, .rpm, .ipk) produced from a recipe.

    • Defined by PACKAGES, FILES, RDEPENDS.
    • Default package = ${PN} (runtime).
    • Subpackages often ${PN}-dev, ${PN}-dbg, ${PN}-doc.

So when you see variables like PN, PV, PR:

  • They originated when everything was called a “package.”
  • In modern Yocto docs they’re described in terms of recipes.

Timeline of Terminology

  • Early OE (2003–2005): “packages” meant recipes.
  • BitBake 1.0 era (2004): variables standardized (PN, PV, PR, SRC_URI).
  • Yocto Project launch (2010–2011): clearer separation of “recipes” vs “packages.”

  • Today:

    • Recipe = build instructions (.bb, .bbappend, .inc).
    • Package = runtime output for the package manager.
    • But variable names still use the historical “package” prefix.