The Callisto User Controller
If you choose to adopt the Callisto User Controller when you run through the Callisto Welcome experience, it will prompt each user accessing Callisto to download and run the Callisto.exe on their desktop.
When you first log in to Callisto you will run through the Welcome Experience. The first task here is to download the controller, unzip it and run it on your computer. Once you've done that it pops up here in the System Tray. Clicking the Callisto icon will take you to the login page for Callisto. Right click will present some options for startup behaviour etc.
With the controller running, when you browse to the Callisto portal your web browser loads the dashboard page from the Callisto website, this includes the SQL queries and all code required to render the dashboard. The controller takes the SQL queries you've just loaded and executes them against your CM database. The resulting data is then used to render the dashboard pages.
If the controller is not running when you try to browse your Callisto portal, a message will be shown offering you the option to download the controller. This is useful if you are on a new/different machine, so you can quickly download and unzip and run the controller, but there is no need to re-download it if you have a copy already, just run the original version once more.
The controller also handles our communications with the Configuration Manager SDK for console actions such as remote control, reboot request etc. Occasionally we'll need to update the controller to support new functions. When this happens we'll notify you but will also see a prompt in the portal to download the new version.