Basic SetupPermalink to Basic Setup
SOS is a collection of hardware that integrates computers and video projectors to display animated images onto the surface of a large sphere. Taken in pieces, the system consists of a sphere situated in a room, surrounded by four video projectors, numbered one to four starting with number one closest to the computer and then going counterclockwise.
The video projectors are connected and driven by the primary computer. Each projector is responsible for its own quadrant of the sphere. The computer has one six output graphics card to support the four projectors and a second graphics card to run the user interface. The computer pulls in content, usually some type of planetary imagery, renders it to an Earth projection, subsets it, and upon command displays it onto the sphere. The computer is responsible for many things, namely among them: running the main user interface to the system, real time data collection, and providing the interface to the automation control protocol. All of the computers use the Linux operating system Ubuntu (currently version 16.04). Most sites buy a “hot” spare that is identical to the primary computer in terms of hardware, as a backup system. All of the software that drives and controls the SOS system is written and maintained by NOAA.
System SpecificationsPermalink to System Specifications
The computer in the SOS system is a standard computer system with mid- to high-end graphics cards.The system is generally specified so that both the primary and spare computers are identical from a hardware perspective to allow easy swapping of components (in case of system failures).
Projectors are usually specified so that they work well in high duty hour environments. Mostly, projectors classified as “board room” projectors meet this requirement. These projectors typically have multiple fans to provide adequate cooling during the day. The projectors are also specified so that they produce a high light output (lumens), mostly in the range of 3500 to 5000 lumens. The supported resolution for the projectors should be at least 1024x768, though higher resolutions are recommended.
An audio system is part of a standard SOS exhibit. A typical setup includes a mixer, microphones, and four speakers. Some of the content that comes with Science On a Sphere® includes a narration track with background music, requiring the use of the audio system. Also, presenters often use the microphones, if available, during large presentations. Each site is responsible for designing their audio system to meet their needs.
Site ConfigurationPermalink to Site Configuration
Each site is configured differently in regards to projector height, distance and resolution. All of this information is stored in /home/sos/sos_stream_control.config if you’re using a SOS version 5.4 and below, or held in /shared/sos/site-config/local_sos_config.json if you’re on version 5.5 or above. The parameters in this file are set during installation and normally should only be changed if the exhibit is reconfigured. Details on what is in this file and a few options you can modify are discussed in Appendix A: SOS Stream Control Configuration File.
Every site also has individual alignment files that are stored in /shared/sos/site-config. In this directory you will find the alignment files. All of these files are included in those that are backed up and synced daily.
SOS CrontabPermalink to SOS Crontab
Cron is a time-based job scheduler that is used to automate processes on the computer. The crontab is the file that contains all the information about the jobs that are scheduled. The SOS computers come with a default crontab that can be edited by each site. Included in the default crontab are hourly real-time data downloads, daily data syncs and backups, and weekly downloads of new datasets. The crontab can also be configured to include the automatic power up and down of the projectors if desired. In a terminal, entering crontab –l will display everything that is included in the cron. For more information about the cron, watch the “How to Edit the Crontab” video tutorials in our tutorials.
NetworkPermalink to Network
The computers are connected via a gigabit network to enable high speed communication and data transport.The primary and spare computers reside in a private, non-routable network space (usually in the 10.x.x.x network range). The primary computer, however, also usually sits on the border between the private SOS network and the sites local Intranet. The primary computer sits at the border of the network to enable outside access for remote systems administration, software updates,and download of real time data from the NOAA servers. While the local, private SOS network is gigabit, the external connection can be whatever the local site supports in their network infrastructure. If supported by the projector infrastructure, the projectors can also be connected to the private network to allow for remote power on/off.
In many cases a Wi-Fi network is also set up to allow use of the iPad SOS Remote App. An existing Wi-Fi infrastructure can be used, or a dedicated Wi-Fi network can be set up for use with SOS. A dedicated Wi-Fi network provides the most responsive control of your SOS system by the app. Doing this in a secure way requires some network expertise. You may need to select a Wi-Fi channel that doesn’t conflict with other Wi-Fi networks, for example. Using the minimum transmitter power that you need is always a good idea. And WPA2 encryption is probably the minimum level of encryption you will want to use. You might want to turn off the beacon identifier for your Wi-Fi router to make it less obvious to casual visitors at your site. You might also consider limiting access to the specific MAC addresses of your portable devices. SOS personnel work with the site staff to determine the best options for each individual site.
User AccountsPermalink to User Accounts
Administrators of Linux sometimes need access to the super user account
(similar to the Windows “administrator” privileges). The super user account in
Linux is called “root”. The password is set at machine installation and can be
changed locally at the site. It is generally considered safer, or at least a
better practice, to not use root directly, but rather use the
sudo command that
temporarily raises a normal users privilege to root for the duration of a
single command. Only the sos user has sudo privileges.
- sos is an administrative account that has the ability to download new data, run the alignment software, install updates and manage the real-time data downloads
- sosdemo is used for day-to-day system operation and running the SOS software. The user sosdemo does not have permission to delete data, edit the software or run alignment. This user is intended to serve as a “safe” mode, where the computer operator will be able to do very little damage to the software or the data
Every process that runs under Linux must have a user id. The SOS system uses two user ids: sos and sosdemo.
BackupsPermalink to Backups
The computers are set to run backup scripts early every morning to push data from the primary computer to the spare computer. In general, all of the data that comes with the system can be retrieved from NOAA, however, there are some data files that are customized to be site specific. Examples of site specific data include the custom playlist data in the SOS home directory, the alignment configuration files that are in the home directory, and any custom or local site content that was developed and installed on the system.
All of the media files and playlist files are synced from the primary to the spare computer so that there is a backup copy on the spare computer. Backup copies of the playlist and alignment files are stored on the spare computer in /shared/sos/site-backup.hostname. In case of failure, the spare computer has a duplicate copy of everything needed, though the alignment files will have to be moved from the backup folder to /shared/sos/site-config. Sites are still encouraged to backup data on a separate system as well. Generally, the playlist and alignment data are just a few megabytes (usually much less). In terms of content, only the content developed by the site needs to be backed up on a separate system. All of the content that comes preloaded on the system is always available from NOAA. The custom content can sometimes be many gigabytes, but is definitely worth backing up.
In addition to syncing the computers, backups are also stored on the local computer in /shared/sos/site-backup.hostname. In this directory, you will find dated files for every day that contain all of the same files that are synced to the other computer (excluding the media tree), including configuration files and playlists. In addition, backups of the playlist files are tarred and stored every time the playlist editor is opened. Those files are in the home folder for each users in a directory called sosrc-backups: /home/sos/sosrc-backups and /home/sosdemo/sosrc-backups.
Software SecurityPermalink to Software Security
We have increased our software security measures starting in SOS version 5.3. SOS now requires a new licensed Wibu CodeMeter security USB dongle before you can do the software upgrade. You can request one using an online SOS Version 5.3.0 Upgrade Request form. Once SOS Support has received your request, a dongle will be mailed to your site. If you run into any problems using the request form you can e-mail firstname.lastname@example.org. We will provide instructions on how to upgrade your system to 5.3 once we have mailed out your new CodeMeter device.
Note that unlike the previous Bluetooth USB devices used in earlier versions of SOS, you will have only one CodeMeter dongle that will be required to be plugged into the computer that is running SOS. This means if you switch to using your backup system, you will also need to physically move the CodeMeter dongle to that machine before you can run SOS. Also, if your site is using Bluetooth to connect your iPad to SOS, you will still need to keep the current dongle keys in place as the Bluetooth software depends on them.