Motivation

I was thinking.. if I can

then I can start experimenting writing an operating system!

I connect to the box with a null-modem cable and communicate with it using a terminal program:

                    4GB addressable memory
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
                           |                                                         null-modem cable
                          CPU  <--  PIC                               UART        <-------------------> 
                          

Design principles