Is it possible to create a fake storage device by software?
I want a similar behavior like a usb stick. It should appear in the filesystem. If I put some data in it, the driver should push it over network.
Is that behavior generally possible?
I want to do that for Windows and Mac OS.
What you’re asking for is called a Virtual File System, and it’s indeed possible. See e.g. this article for an example of making one: http://www.flipcode.com/archives/Programming_a_Virtual_File_System-Part_I.shtml