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Luckily Tesla isn't very space or money limited with this pretty ciritcal component. An SD card would make life easier for everyone, as the logs could be easily read out and the booting OS changed - yay for actually owning the device you paid for. But wait: That's not something Tesla wants.



eMMC is literally the equivalent of an SD card soldered down to the PCB. It’s more mechanically stable and also way faster.

In my experience, removable SD wouldn’t hold up to an application like this.


An SD card might work fine if it is mounted properly. The slot found on a Raspberry Pi would not at all be sufficient.

If it were held in and held against some robust contact pins it likely would be fine, even under automotive conditions. There are SIM card slots that are used on heavy vehicle computers and controllers (the ones that run the engine and so on) that are robust enough to hold a SIM card in place for years of excessive daily vibration.


Whenever I drop my phone I see the "SimProcessor" service spinning up...

I suspect that designing reliable spring contacts isn't as easy as it seems...


Yeah, phones aren't designed to have robust SIM slots, they're designed to be thin, so they use very low profile SIM cradles that are not robust to impact.

The trade-offs for a high vibration environment are very different.


The actual logs Tesla seem interested in (including the stills of things they are interested in) get written to a removable SD Card before getting uploaded to the Tesla mother-ship.

You are not wrong that a soldered eMMC (compared to a eMMC held by a ZIF or a removable SD Card) would be more mechanically stable and potentially faster (A fast uhs-ii sd card compared to a cheap slower eMMC for example), just saying that Tesla already use removable SD cards in production cars today (which doesn't brick your media unit if it dies or dislodges).

Storing the OS on a removable SD Card is (imo) a bad idea, but if they are really interested in these logs they already have a easier to replace removable storage "drive" they could write the logs to instead of burning up the eMMC.


Or just add an SD card reader on the board and output the logs there if they need it so much, and keep the rest on the EMMC.




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