I don't use a TI-84 and some half-done research didn't reveal anything useful.
I was writing a more detailed post with insights into multithreading and interrupts, etc... But, you see, my keyboard has these keys on it that offer the "feature" of navigating in your page history. (The web back/forward keys.) That's great and all, except they're near the up arrow key. (The top row: web back, up arrow, web forward; the bottom row: left arrow, down arrow, right arrow. All keys have the same dimensions and are spaced evenly.) So, while I was typing, I accidentally offset my hand a little bit. This eventually caused me to navigate backward a few pages. I thought to myself, "No big deal. I'll just navigate forward and all my text will still be there." Except, somehow there was a redirect loop on the "forum.thegamecreators.com" page. It wouldn't go past that page in my history, it just kept on reloading that. I tried navigating directly back to this page, but the web browser refused to load the page. So I navigated back manually (following links), which of course erases all of the text in my post.
Forum feature suggestion: Drafts.
Anyway, I was going to mention that you should consider that key presses cause interrupts to be triggered, which the processor handles by switching contexts to the appropriate interrupt handling routine, which is registered by the OS. (At least that's the case for x86, but is likely the case for the TI processor too... but I don't know for sure.) If the OS is configured to recognize certain combinations (like Ctrl + C to cancel the current job) then the OS can gain control from an app that "has full control." Also, multi-threading does not mean extra control. The OS can gain control in other ways; like the key combination I mentioned above.
