BBC B Edit
Here's the source file for the !Boot file. First it loads Edit into sideways RAM bank 11, then it programmes the BREAK key to insert characters into the keyboard buffer to change the Edit mode to K - to show the function key strip on screen. This is because, without CMOS RAM in the BBC B, the configure screen mode setting for Edit is not stored and reverts to default, but I prefer "K" mode. Then it stars Edit by changing the language to ROM 11, and changes the screen mode to K.