==========================
TanoWrt Variables Glossary
==========================

This section lists specific variables used in the :ref:`TanoWrt core layer <meta-tanowrt>`
and gives an overview of their function and contents.

A B C
D E F
G H I J
K L M
N O P Q
R S :term:`T <TANOWRT_PARTUUID_BOOT>`
U V W X Y Z

.. glossary::
   :sorted:

   :term:`TANOWRT_PARTUUID_BOOT`

      This variable contains the UUID for the boot partition, specific to each supported board.
      It is usually specified in the machine configuration file. For example,
      :tanowrt_git_blob:`qemuall.inc </meta-tanowrt/conf/machine/include/qemuall.inc#L27-L32>`
      has the following UUID definitions:

      .. code-block:: bash

         TANOWRT_PARTUUID_BOOT        = "bbefcb9e-ac94-43fc-8be2-0023a70c0722"
         TANOWRT_PARTUUID_OVERLAY     = "4473a134-2531-4ab1-a5f9-dfa54376eb78"
         TANOWRT_PARTUUID_ROOTDEV_A   = "d4997f99-3f39-4952-9433-602b66222be5"
         TANOWRT_PARTUUID_ROOTDEV_B   = "fd4aab45-0ed8-48dc-8b07-6514336e2ac1"
         TANOWRT_PARTUUID_KERNELDEV_A = "a1a55b33-b1c9-4226-b2f6-0d7d901f040f"
         TANOWRT_PARTUUID_KERNELDEV_B = "d35fdb7b-4042-4f75-a4af-8983f9584b47"

   :term:`TANOWRT_PARTUUID_KERNELDEV_A`

      This variable contains the UUID for the linux kernel partition for system A,
      specific to each supported board. It is usually specified in the machine configuration file.

   :term:`TANOWRT_PARTUUID_KERNELDEV_B`

      This variable contains the UUID for the linux kernel partition for system B,
      specific to each supported board. It is usually specified in the machine configuration file.

   :term:`TANOWRT_PARTUUID_ROOTDEV_A`

      This variable contains the UUID for the read-only root filesystem for system A,
      specific to each supported board. It is usually specified in the machine configuration file.

   :term:`TANOWRT_PARTUUID_ROOTDEV_B`

      This variable contains the UUID for the read-only root filesystem for system B,
      specific to each supported board. It is usually specified in the machine configuration file.

   :term:`TANOWRT_PARTUUID_OVERLAY`

      This variable contains the UUID for the overlay partition (user data),
      specific to each supported board. It is usually specified in the machine configuration file.

   :term:`TANOWRT_ENABLE_OVERLAY_RESIZE`

      This variable enables or disables the automatic overlay partition extending feature.
      If this feature is enabled (set to ``1``), at the first system boot, it will attempt
      to extend the overlay partition to the entire storage space (SD card, USB flash drive, etc.).
      By default this feature is disabled (set to ``0``) and can be set individually for specific
      machines in their configuration.

      By default, the extending is done to the entire available space. To limit the available size
      for extending, you can use the :term:`TANOWRT_OVERLAY_RESIZE_LIMIT_SECTORS` variable.

   :term:`TANOWRT_OVERLAY_RESIZE_LIMIT_SECTORS`

      Limit overlay partition size in sectors (set to ``0`` for disabling limit).
      Value of this variable is used to limit the available size during automatic
      overlay partition extending, which is controlled by the :term:`TANOWRT_ENABLE_OVERLAY_RESIZE`
      variable.

      Variable value is specified in sectors (usually 1 sector equals 512 bytes).

      By default, overlay partition size limit is disabled (set to ``0``).