Hardware Screencasting Help Here is my situation. I'm doing a series of lectures for a Udemy course and I need to show people how to boot into tails from a USB drive. Obviously while configuring the bios and when in the new O.S it is impossible to run a software screencast solution thus I need some form of hardware to frame grab. 

I've never done this before and I need some help to understand the basic concepts and what I should buy. I understand this question isn't quite in a stackexchange format thus at the very least if you could point me to a forum that could answer this question or a tutorial you think would be helpful, then I'd be very grateful
You can use a graphics card that has a HDMI output connector.

Instead of connecting it to a monitor/TV you can connect it to a camera or a VCR that has HDMI input. This way you should be able to record anything that is shown at the card.