doc(location):Describe how to disable swap file

[EVA-2020-02.git] / doc / location / README.org

diff --git a/doc/location/README.org b/doc/location/README.org
index 92e73b7958d718c56dc7c2a2da832642a25706de..ebabe81e84a8f32f52335c99ed2d50b396c7055d 100644 (file)
--- a/doc/location/README.org
+++ b/doc/location/README.org
@@ -1,7 +1,10 @@
 * Location Logging
 This document was created by Steven Baltakatei Sandoval on
-<2020-06-29 Mon 12:14> under a [[https://creativecommons.org/licenses/by-sa/4.0/][Creative Commons BY-SA 4.0 license]]. It
-was updated by Steven Baltakatei Sandoval on <2020-06-29 Mon 18:39>.
+~2020-06-29T12:14Z~ under a [[https://creativecommons.org/licenses/by-sa/4.0/][Creative Commons BY-SA 4.0 license]]. It
+was updated by Steven Baltakatei Sandoval on ~2020-06-30T17:13Z~
+#+TITLE: Ninfacyzga-01 Manual
+#+AUTHOR: Steven Baltakatei Sandoval
+#+EMAIL: baltakatei@gmail.com
 ** Narrative
 Ninfacyzga-01 records (logs) its position in time and space using a
 [[https://en.wikipedia.org/wiki/Satellite_navigation_device][GPS receiver]]. The NMEA location data produced by the receiver is
@@ -72,7 +75,7 @@ An ~ssh-rsa~ or ~ssh-ed25519~ SSH public key string may be used instead of
 the bech32 public key string produced by ~age-keygen~ for convenience.
 
 Help information for ~age~ is available by running ~$ age --help~.
-***** Encryption
+***** Encryption Commands
 Files may be encrypted to several recipients using a command similar to:
 #+BEGIN_EXAMPLE
 timeout "60s" gpspipe -r | gpsbabel -i nmea -f - -o gpx -F | age \
@@ -86,7 +89,7 @@ In this example, the strings beginning with ~age1...~ are
 bech32-formatted public key strings. 
 
 
-***** Decryption
+***** Decryption Commands
 Files may be decrypted using a command similar to:
 
 #+BEGIN_EXAMPLE
@@ -108,7 +111,6 @@ conflict so a simple stacking and soldering with long header pins is
 possible.
 
 **** Software Setup
-
 ***** Install Executables
 
 Install Raspbian 10 Buster onto an SD card image. See the Raspberry Pi
@@ -128,21 +130,73 @@ Install ~syncthing~ for log file transfer capability.
 Place ~age~ binary (the one compiled for ARM CPU architecture for
 Linux) in ~$HOME/.local/bin~.
 
+***** Disable Swap File
+Since standard Raspbian 10 install involves copying unencrypted file
+system image to SD card which is mounted by the Raspberry Pi, system
+memory may be written to disk in the form of a Swap file as described
+[[https://ideaheap.com/2013/07/stopping-sd-card-corruption-on-a-raspberry-pi/][here]]. In order to reduce the chance that location log data is ever
+written to disk, swap file functionality must be disabled.
+
+To view the status of the swap file in Raspbian 10, run ~free -m~:
+
+#+BEGIN_EXAMPLE
+pi@ninfacyzga-01:~$ free -m
+              total        used        free      shared  buff/cache   available
+Mem:            432          86          36          21         309         268
+Swap:            99           0          99
+#+END_EXAMPLE
+
+The swap file may be disabled by:
+
+#+BEGIN_EXAMPLE
+pi@ninfacyzga-01:~$ sudo dphys-swapfile swapoff
+pi@ninfacyzga-01:~$ sudo dphys-swapfile uninstall
+pi@ninfacyzga-01:~$ sudo update-rc.d dphys-swapfile remove
+pi@ninfacyzga-01:~$ free -m
+              total        used        free      shared  buff/cache   available
+Mem:            432          96          33          22         302         258
+Swap:             0           0           0
+#+END_EXAMPLE
+
 ***** Automatic Start Configuration
 
 Edit the user cron job list with ~$ crontab -e~ to add the following
 lines:
 
 #+BEGIN_EXAMPLE
-0 * * * * /bin/bash /path/to/bkgpslog --output $HOME/Sync/example_dir
+0 * * * * /bin/bash ~/bkgpslog --output ~/dir
 
-@reboot /bin/bash /path/to/bkgpslog --output $HOME/Sync/example_dir
+@reboot /bin/bash ~/bkgpslog --output ~/dir
 #+END_EXAMPLE
 
-The first line will run ~bkgpslog~ at the start of every hour.
+The first line will run ~bkgpslog~ at the start of every hour and save
+output files to the ~dir~ directory in your home folder.
 
 The second line will run ~bkgpslog~ when the system starts up.
 
+~/bin/bash~ tells ~cron~ to run ~bkgpslog~ with Bash.
+
+If encryption and compression are required, then the appropriate
+options must be added. The lines that must be added via ~$ crontab -e~
+may resemble:
+
+#+BEGIN_EXAMPLE
+0 * * * * /bin/bash ~/bkgpslog -c -e -r age1z2...qkv6p -o ~/dir
+
+@reboot /bin/bash ~/bkgpslog -c -e -r age1z2...qkv6p -o ~/dir
+#+END_EXAMPLE
+
+The ~age1z2...qkv6p~ is an ~age~ public key string. Please see the
+[[*Key Generation][Key Generation]] section for an explanation.
+
+The options are:
+
+: -c : tells bkgpslog to compress output
+: -e : tells bkgpslog log to encrypt output
+: -r : tells bkgpslog to interpret the next argument as a pubkey string
+: -o : tells bkgpslog to write output files to the directory represented
+:        by the next argument
+
 ***** Log Transfer Configuration
 Log files may be shared to other machines via ~syncthing~. See [[https://docs.syncthing.net/][this]]
 manual for how to set up a shared folder and add Ninfacyzga-01 as a