[LAD] RT

Is it possible to configure a system (included changes to programs) so that nothing can interfere with a few RT threads? I have an audio and video thread in a program, and they are running as SCHED_FIFO, but so many things can interfere with those two threads, such as USB plugs/unplugs, cron log rotations, disk access (PIO flash disk), ssh logins, etc. I really would like to shore up performance here. I am not using Ingo's RT patches, but I still see people talking about turning off things like cron and server processes to prevent xruns when using Ingo's RT patches. While I have turned off cron, turning off sshd and the web server aren't options. I want to instead somehow make sure that neither can every interfere with the AV threads, even if it means that SSH and web traffic are extremely slow.