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Former Tesla Firmware Engineer Discusses the System

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Re: Former Tesla Firmware Engineer Discusses the System

#141

Post by coldtea »

BugsJustFindMe wrote: post #74
8_hours_ago wrote: post #52

Earlier quoted context omitted.

> 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).

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.

>I promise that their pid control isn't an Electron app.

Given all the wtf stuff in TFA, it might very well be...

Re: Former Tesla Firmware Engineer Discusses the System

#142

Post by da02 »

JumpCrisscross wrote: post #137
8_hours_ago wrote: post #52

Earlier quoted context omitted.

> 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.

(I don't have any experience with real-time applications.) What are some things they had to do to harden the kernel?

Re: Former Tesla Firmware Engineer Discusses the System

#143

Post by luma »

I found this post [1] interesting:

> ol' musky isn't totally paranoid - we did catch bad actors doing stuff and they were nailed to the wall. finding a real apt in your network can be some next level shit

That looks like confirmation that there really were internal threats found as claimed by Elon.

[1]: https://forums.somethingawful.com/showthread.php?threadid=38...

Re: Former Tesla Firmware Engineer Discusses the System

#144

Post by teslatech »

mzs wrote: post #6
toomuchtodo wrote: post #2

Source: https://forums.somethingawful.com/showthread.php?threadid=38... (Pages 62 through 68) Left as a reference, citation. Mods: Wouldn't suggest changing to this URL, UX is pretty ick, easier to read the Twitter screenshots.

Any way to know those posts are not just the fantasy of a troll?

He mentioned the slack compromise, that happened and was not publicly disclosed.

Re: Former Tesla Firmware Engineer Discusses the System

#145

Post by shittyadmin »

JumpCrisscross wrote: post #137
8_hours_ago wrote: post #52

Earlier quoted context omitted.

> 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.

Not just that but holy shit some of those commercial RTOSes have major issues. I work in aerospace and we recently used one where the whole system would crash after ~230 days of uptime.

At least with Linux you're getting a system that's been used so much that all major issues like that are ironed out. Nothing beats a few million testers.

Re: Former Tesla Firmware Engineer Discusses the System

#146

Post by coldtea »

mlaretallack wrote: post #99
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.

Agree completely. Hard real time is possible with Linux, we use it for sub millisecond control of Traffic Lights. The only issue we ever hit is proving that the code running is the stuff we expected to run.

>we use it for sub millisecond control of Traffic Lights

Why would anyone need "sub millisecond control of Traffic Lights"?

Traffic lights are mission critical systems, of course, but even millisecond precision should be more than enough, and possibly even 0.5x-1 second precision...

Re: Former Tesla Firmware Engineer Discusses the System

#147

Post by gmueckl »

Aloha wrote: post #93
8_hours_ago wrote: post #52

Earlier quoted context omitted.

> 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).

They could have used RTEMS (was designed for missiles) - on some level, if you design accordingly, you dont need a realtime operating system anymore - you can get by without it, and its easier to find people to design software in my opinion for not an RTOS

How would you design a complex control software for a realtime application so that you don't need an operating system? I don't see how.

Re: Former Tesla Firmware Engineer Discusses the System

#148

Post by coldtea »

JumpCrisscross wrote: post #137
8_hours_ago wrote: post #52

Earlier quoted context omitted.

> 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.

>Same reason SpaceX eschews radiation-hardened processors for redundant off-the-shelf cores

A devil-may-care throw-caution-to-the-wind cavalier attitude?

>supplier competition

I stand corrected. And I'm never buying a Tesla or property even remotely close to SpaceX launch sites...

Re: Former Tesla Firmware Engineer Discusses the System

#149

Post by coldtea »

bipson wrote: post #94
8_hours_ago wrote: post #52

Earlier quoted context omitted.

> 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).

Any substantiated argument why using Linux "is a huge accident waiting to happen"? Did you know that Linux can handle hard RT, if you use the right hardware (and maybe the right kernel/patches).?

>Did you know that Linux can handle hard RT, if you use the right hardware (and maybe the right kernel/patches).?

Does TFA (which sure, is for Tesla, but same leadership) describe an environment where people use "the right hardware"?

Re: Former Tesla Firmware Engineer Discusses the System

#150

Post by huehehue »

arcticfox wrote: post #120
mlaretallack wrote: post #99

Earlier quoted context omitted.

Agree completely. Hard real time is possible with Linux, we use it for sub millisecond control of Traffic Lights. The only issue we ever hit is proving that the code running is the stuff we expected to run.

> Agree completely. Hard real time is possible with Linux, we use it for sub millisecond control of Traffic Lights. Out of curiosity, why do traffic light controls need to be that precise?

Venturing a guess -- there's either some X% accuracy standard required by the government for who-knows-what reason, or it's for red light cameras and ticketing systems.

"Ironically, the biggest concern with red-light camera systems is that they are so precise. They measure a driver’s speed and exact location within a fraction of a second — but do not leave any wiggle room for the errors of traffic signals such as inconsistent yellow light times"[0]

If there's not an accuracy threshold for safety reasons, there's gotta be one when traffic ticketing revenue is on the line (also I guess determining fault at accidents, vehicular manslaughter cases, etc.)

[0] https://www.mercurynews.com/2014/06/06/red-light-cameras-how...

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