Comment by squeedles
9 hours ago
Was excited to hear that they have a lower power rad-hard snapdragon system going into the new missions! The RAD 750 is basically a 30-year old IBM RS-6000. Very well known, but has been the goto CPU for way longer than I thought it would be.
Anyone who wants a more in depth look at how patches keep getting applied to what's essentially a radhard version of the candy shell Mac processors can head over to this link -> https://www-robotics.jpl.nasa.gov/media/documents/Curiosity_...
Leveraging VxWorks you effectively have 3 different ways this software gets updated.
Hot Patch -> Do it live! where you modify the RAM with compiled code so that the changes persist until next reboot.
Cold Patch -> Same as a hot patch, except this time you actually copy the contents into non-volatile memory. VxWorks has a really slim profile and thus this helps keep the size manageable to continue doing science experiments.
Full Updated -> Basically a clean install gets burned in.
It turns out GNC is significantly easier than rendering a video game. You don't even need that fast of a control loop. Your bigger concern is legitimate real time processing over raw compute power.
Otherwise, we have shown, if you need power, send the astronaut up there with a laptop. Which is far easier to replace and upgrade as years advance.