Ontopic A Thread About Butt Mustard, For Those Who Drive Automobiles

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Older Teslas going caput. Oops

Ugh. Writing small bits of data frequently to a log file, on a small flash partition, you're gonna have a bad day.

We had a Fortinet firewall at work with the same bug, that would brick itself after several months after wearing out its flash, and they'd send us another one, and that would brick itself, and they'd send us yet another one. We ended up replacing the thing with something else because they weren't making any effort to fix the problem.
 
I briefly perused a short article yesterday in Car and Driver or Motor Trend mag about battery swap stations that the Chinese have nearly perfected. The cars are designed to have battery swaps done easily (by robots!) in three minutes.
 
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Older Teslas going caput. Oops

I'm surprised it could even last 4 years. I'm sure the logging is insane. Logs can be compressed to fuck, but I wonder how much cellular data these cars are chewing through as a whole.
 
I'm surprised it could even last 4 years. I'm sure the logging is insane. Logs can be compressed to fuck, but I wonder how much cellular data these cars are chewing through as a whole.
Issue isn't that the cars are running out of space, it's flash longevity being murdered by small/frequent writes.

Adding 1 line to the end of a text file, stored in an e2fs partition on an MMC card, probably changes a megabyte worth of memory on the bare NAND chip inside the eMMC device. You're changing the file, you're changing the filesystem information (file size, last modified date), and internally the eMMC card has its own layer of management/wear leveling/etc that makes its bare NAND look like a block device. One little file change snowballs to a whole lot of flash activity and wear.

You can do small/frequent writes to flash (it's a pretty significant part of my day job, making autonomous data logging gear) but it requires a bit more more thought than Tesla's "whatever, the eMMC just looks like a hard disk" mindset.
 
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Worth noting that there's no shortage of people killing SD cards on Raspberry Pi boards, via the same method.
Learned that lesson myself years ago on an SBC that I was doing smoothwall on (with a CF card mounted as /).

Gotta keep /var mounted in RAM, then either flush it to disk periodically or let the logs go when you shut down.
 
Issue isn't that the cars are running out of space, it's flash longevity being murdered by small/frequent writes.

Adding 1 line to the end of a text file, stored in an e2fs partition on an MMC card, probably changes a megabyte worth of memory on the bare NAND chip inside the eMMC device. You're changing the file, you're changing the filesystem information (file size, last modified date), and internally the eMMC card has its own layer of management/wear leveling/etc that makes its bare NAND look like a block device. One little file change snowballs to a whole lot of flash activity and wear.

You can do small/frequent writes to flash (it's a pretty significant part of my day job, making autonomous data logging gear) but it requires a bit more more thought than Tesla's "whatever, the eMMC just looks like a hard disk" mindset.
which is strange, cause automotive hardware design is usually super robust.
 
yeah, but theres industry standards required for this stuff that you dont get to put your vehicles on the road if you dont follow

IATF 16949, AEC-Q100 and AEC-Q200

citation: https://www.qorvo.com/design-hub/bl...ndards-101-what-qualification-really-gets-you
I'm sure that Tesla's been following those as they patch their cars about once a month.

There's no possible way that an engineer who just wants those logs could have snuck anything in under the bar for a release, no way at all.
 
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you really have a big old hard-on for elonhate eh.
I have a hard on for bad design and bad engineering that leads to poor safety performance, poor customer satisfaction, and excessive waste.

My main issue with Elon is the cult that has sprung up around him that ignores all of these things and thus allows him to get away with them.
And, you know, his random attacks on people that question him.
 
I have a hard on for bad design and bad engineering that leads to poor safety performance, poor customer satisfaction, and excessive waste.

My main issue with Elon is the cult that has sprung up around him that ignores all of these things and thus allows him to get away with them.
And, you know, his random attacks on people that question him.
the pedogate thing was a super dick move.
 
which is strange, cause automotive hardware design is usually super robust.
I'm sure the hardware is AEC-Q, but the UI software is written by a team of young hackers vs graybeards.

All I hope is the major software in the big power electronics / safety equipment / whatever is properly graybearded.
 
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