Is there ANY way using C, C++, and/or assembly that lets you directly access memory of a computer? Like the actual basic hard drive in bytes or something. I'm interested in OSs and the very ground-level stuff, like memory and stuff, so yeah.. I'm all about manipulating the lowest-level stuff.
As a side note, I'm very interested in security. Does anybody have any very simple firewall code? (not so much antivirus.. although that is interesting). Firewall or any GameGuard/XTrap type stuff?