--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/opt-freecalypso-tree	Sun Nov 04 21:55:19 2018 +0000
@@ -0,0 +1,48 @@
+The /opt/freecalypso host directory tree used by the present FC host tools
+package and by various add-ons to it does NOT follow the traditional Unix/Linux
+file system hierarchy standard (FHS), instead it is a highly specialized
+directory tree that is meant to be private to FreeCalypso, with its structure
+defined solely by the Mother and no one else.  The following subdirectories are
+currently defined:
+
+aud-*: these directories appear if you install our optional
+fc-audio-config package, and contain subtrees to be uploaded by
+production line scripts into target device FFS under /aud via fc-fsio.
+
+batteries and charging: these subtrees come from fc-battery-conf
+(optional just like fc-audio-config) and are meant to be used with
+fc-fsio write-battery-table and write-charging-config commands.
+
+bin and include are the only subdirectories under /opt/freecalypso
+which follow traditional UNIX directory layout; include was added so
+that packages external to the core FC host tools package like
+fc-rfcal-tools and freecalypso-ui-dev can use rvinterf headers.
+
+gcc: the recommend install location for our ARM7 gcc toolchain is
+/opt/freecalypso/gcc.
+
+helpfiles subdir contains help files for those FC host utilities which
+implement a help command.
+
+loadtools subdir contains hardware parameter files and init scripts
+which underlie the all-important -h option to fc-loadtool, fc-iram and
+fc-xram, collectively known as loadtools.
+
+rfcal subdir only appears if you are doing RF calibration and install
+fc-rfcal-tools, and some of the necessary config files under that
+subdir you have to create yourself using your own RF knowledge specific
+to your particular setup.
+
+target-bin contains ARM7 target binaries used under the hood by
+loadtools.
+
+The basic minimal form of the /opt/freecalypso tree is populated when
+you install FC host tools, but it is further enriched if and when you
+install further add-ons (fc-audio-config, fc-battery-conf,
+fc-rfcal-tools) which are more specialized and not required for all
+users.  I expect to have more additions in the future: for example,
+when we start using the Melody E1 mechanism in our planned FC Libre
+Dumbphone, there will be a FreeCalypso ringtones package that will
+install E1-format melody files somewhere under /opt/freecalyso, to be
+subsequently uploaded into the actual phones via fc-fsio, initially at
+production time and optionally by end users.