Setting up a gallery installation

RDEX is a gallery installation, one component of which runs from a computer with the video output projected and an internet connection to upload data. The technical requirements for the installation involve setting up a laptop so that everything starts up automatically when it is turned on, with error recovery in case of unforeseen bugs.

Create a LiveUSB

The usual procedure.

Configure hardware drivers

RDEX needs accelerated OpenGL with hardware shader support, which usually requires installing proprietary drivers.

User setup

Create a new user called rdex without administration rights for increased security. The installation will run as this user.

The su command allows you to switch users, for example sudo su rdex. The workflow is to do the set-up logged in as your own user switched to the rdex user in a terminal, as logging in as the rdex user would start the installation.

Configure displays

RDEX runs fullscreen on the external video output of a laptop with its lid shut. Monitor power saving (DPMS) and screen blanking must be disabled.

Automatic login to custom user

As a user with administration rights, set up the login manager to automatically log in as the installation's user after a short delay (enough time for a human to log in as a different user when necessary).

Automatic start of the software

Create a shell script to start everything up. Create a desktop file in the autostart folder to launch that script.

Devil's Pie is a handy tool to tweak the window manager settings for applications, in this case to move the RDEX output window to the external output, remove window manager decorations, and maximize it to full screen.

The script runs a loop that restarts the installation in case the custom software crashes.

Testing

Once everything is prepared, make a backup of the key with dd. Then try rebooting and see if it all works. If everything is set up correctly, revert to the pristine image, and save it for the opening ceremony. Otherwise fix the problems and repeat the process.

Remote debugging

OpenVPN can be used to access machines that are behind NAT barriers. SSH through the VPN to inspect the system. The output of the autostart script will be logged in the xsession-errors file. In RDEX's case, if it is working correctly there'll be new messages quite often, so tail -f for realtime updates.

Puredyne/RDEX gallery installation

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