Non maskable interrupt

I recently developed a web based picture viewer useful to turn a tablet (or, actually, every device that has a web browser in it) into a digital photo frame. This tool is a client/server application that can be used on every device to display a slideshow of some pictures that are stored on a server (or NAS, etc.) in your local network. It is composed of a client part that retrieves the list of folders from the server and allows the user to select which folders the pictures to be displayed are in. Then it starts asking the server one picture at a time. The server part is based on node.js and it is so simple that can be run on a Raspberry Pi device (I actually run it on a RPi device with a nodejs version as old as v0.10.9). This part retrieves the list of folders and then one picture at a time when requested by the client. The server can be accessed by multiple clients at once because each one has its own session with a separate list of pictures to be displayed. If you are