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Former Tesla Firmware Engineer Discusses the System

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Re: Former Tesla Firmware Engineer Discusses the System

#131

Post by gapo »

js2 wrote: post #102
BugsJustFindMe wrote: post #74

Earlier quoted context omitted.

As a person who used to write navigation and control software for autonomous vehicles who occasionally gets downvoted for telling people that you really don't need a fancy RTOS for this stuff, you really don't need a fancy RTOS for this stuff. Linux is a very common platform for highly responsive robotic systems. I promise that their pid control isn't an Electron app.

Also, an RTOS is susceptible to priority inversion[0] so it’s not necessarily a panacea. 0. which infamously occurred on the Mars Pathfinder. https://www.rapitasystems.com/blog/what-really-happened-to-t...

There are solutions to priority inversion. This is an old limitation that is now days even taught in school.

Any decent RTOS should have Priority inheritance that should avoid this.

Pointing to this one things as RTOS issue isn't really an accurate portrayal of current RTOS capabilities.

Re: Former Tesla Firmware Engineer Discusses the System

#132

Post by Moter8 »

liber8 wrote: post #31
oxymoron wrote: post #14

Earlier quoted context omitted.

Remember the Toyota uncontrolled acceleration bug and the report that came as a result of the trial. It seems like software is a bit of a second thought for some incumbents too.

Not sure if you're being sarcastic or not, but the Toyota issues were not caused by any software bug. Most cases were caused by people hitting the wrong pedal. The others were caused by floor mats that were a bit too long, causing the gas pedal to stick. https://www.caranddriver.com/features/its-all-your-fault-the...

"Sorry, this content is not available in your region".

Welp, sadly I am not able to read your source.

Re: Former Tesla Firmware Engineer Discusses the System

#133

Post by beaconstudios »

ryana wrote: post #73
sz4kerto wrote: post #8

Why is this interesting or surprising? Of course almost all challengers have hacky tech under the hood because they don't have the resources. Winning from that position is possible not because of generally better tech but by delivering something that the incumbents don't. Remember the demo of the first iPhone (vs the huge expertise of Nokia). Or how Microsoft won the desktop starting from a single user, cooperative m…

> Of course almost all challengers have hacky tech under the hood because they don't have the resources. Tesla has a larger market cap than Ford, GM, or Honda.

Market cap isn't a measure of the resources a company has at its disposal.

Re: Former Tesla Firmware Engineer Discusses the System

#134

Post by gapo »

crististm wrote: post #109
kevan wrote: post #59

Earlier quoted context omitted.

I'm not familiar with this space but I'm pretty sure there are hard realtime kernels for linux. I'd hope they're using one.

Technically there used to be (still is?) such a thing as realtime Linux but not _for_ Linux (which you probably meant the userland?). Regardless. There are many and far better alternatives to Linux for real time applications.

RT Preempt / Preempt-RT patch still exists. It slowly is being integrated into mainline as per everyone's wishes but it is still a thing.

Re: Former Tesla Firmware Engineer Discusses the System

#135

Post by intern4tional »

eequah9L wrote: post #88
lowry wrote: post #25

Earlier quoted context omitted.

It is common knowledge that Toyota uncontrolled acceleration bug was completely imaginary, see for example http://revisionisthistory.com/episodes/08-blame-game

Check out this, and the linked court transcripts linked therein: http://www.safetyresearch.net/blog/articles/toyota-unintende... The security researchers who were expert witnesses in the Toyota case and that analyzed Toyota's source code testified in court that they managed to reproduce the unintended acceleration with a real car on a dynamometer.

The linked trial testimony says otherwise. The engineer states he found bugs, and theoretically it might be possible he was unable to reproduce. Further, he evaluated the software against his own coding standard which was a variant of another.

The engineer was questioned:

" Q. Now, you have not reproduced in vehicle testing your 25 theory that there's a software bug that opens the THIS TRANSCRIPT IS NOT PROOFREAD 30 1 throttle and then the task dies, have you? 2 A. No."

From page 245. Further reproduction questions were all answered with a no further.

To get a successfully task death failure (what the engineer wanted to happen) the engineer had to modify the source code.

Further in the limited testing even with modifications, the failsafe triggered 100% of the time.

Your statement is incorrect.

Re: Former Tesla Firmware Engineer Discusses the System

#137

Post by JumpCrisscross »

8_hours_ago wrote: post #52
ddevault wrote: post #11

I used to work at SpaceX on the team that did a piece of software called "WarpDrive". It was a massive monolithic ASP.NET application, with large swaths done with ASP.NET WebForms and a slow frontier of ASP.NET MVC gradually growing when I was working there. This application was responsible for practically everything that ran the factory: inventory, supply chain management, cost analysis, etc. Elon is a big Windows f…

> the rockets fly with a heavily customized Linux install My jaw hit the floor the first time I heard this. Why Linux instead of an RTOS?? Apparently Tesla's autopilot also runs Linux, which seems like a huge accident waiting to happen (pun intended).

> Why Linux instead of an RTOS?

Same reason SpaceX eschews radiation-hardened processors for redundant off-the-shelf cores: supplier competition. There aren't many RTOS engineers on the market; there are many Linux engineers. Once they got over the cost of hardening the kernel, SpaceX found itself at a scaling advantage versus RTOS-based competitors.

Re: Former Tesla Firmware Engineer Discusses the System

#140

Post by joering2 »

agumonkey wrote: post #77
agildehaus wrote: post #61

Earlier quoted context omitted.

Google's self-driving cars run a modified Ubuntu. Or did, last time they talked about it. https://www.youtube.com/watch?v=7Yd9Ij0INX0

I'm sure anything embedded is almost nothing like the pre-modified stock. The few paper I've read from embedded people is that they know how and will strip everything down until things are like they need.

Ubuntu and Centos come pretty naked; what would you strip and why?

Im asking because I run few instances with very heavy traffic and have no issues whatsoever. Just added nano and fail2ban and it runs with no issues for about 2 years now.

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