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Former Tesla Firmware Engineer Discusses the System

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Re: Former Tesla Firmware Engineer Discusses the System

#181
post #94

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).?

Certification. Many commercial RTOS's are already certified to ASIL-C or ASIL-D, which requires extensive testing to verify that the system will work as designed and every code path is covered by tests. Products exist like Automotive Grade Linux, but you will have to go through the verification and certification process yourself which isn't quick or cheap. I'm not even sure it's possible to certify Linux to ASIL-D.

So yes, I'm sure that Linux can work. But it will be difficult to prove to auditors that it will always work.

Re: Former Tesla Firmware Engineer Discusses the System

#182

Earlier quoted context omitted.

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.

Ubuntu is certainly not known as a lightweight distro.

Re: Former Tesla Firmware Engineer Discusses the System

#183

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).

Some of the rationale for the flight software design is explained in https://lwn.net/Articles/540368/

Re: Former Tesla Firmware Engineer Discusses the System

#184

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.

you really don't need a fancy RTOS for this stuff

maybe you don't, but genuinely curious how do you validate/guarantee scenarios then?

Re: Former Tesla Firmware Engineer Discusses the System

#185
post #51

They've been going 100mph for years now. It doesn't come as a surprise to me that they haven't gone back and made it pretty. While not even remotely on the same scale, I just spent 3 weeks building an app as fast as possible because my client's old one was causing 75% of their support calls. The code isn't pretty, but it works and it works a lot better than the old one. I know deep down that code is going to stay ugl…

So one ugly hack was replaced with another somewhat less ugly hack, which will be replaced by another hack at a later date.

Sounds like every corporate environment I ever encountered, and Tesla it seems. It usually happens becuase they have the money to do it wrong multiple times rather than no choice but to get it right the first time.

Re: Former Tesla Firmware Engineer Discusses the System

#186

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…

>Elon is a big Windows fan and pushed hard to run the whole shop on Microsoft tech wow - this is surprising to me and wasnt mentioned in the biography - any ideas why ?

Probably related to his use of Windows early on at home and at Zip2, PayPal, etc.

Re: Former Tesla Firmware Engineer Discusses the System

#187

Earlier quoted context omitted.

> 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...

I would imagine commoditization generally increases - those variables which market values. In this case I presume the variables include reliability since that stuff is probably used in IoT systems where minimizing maintenance can be probably considered am asset.

Although I don't know the market. It might screwed by some weird market dynamic.

Re: Former Tesla Firmware Engineer Discusses the System

#188
post #114
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…

Especially considering that the engineer was partially blaming Bosch as a supplier that made these processes necessary. Bosch supplies VW (includes Audi, Seat, Skoda, ...) and various other large incumbents, as one of the biggest car manufacturer supplier. Why do people think they are considerably better off? Their practices are often equally ridiculous and dangerous. As a rat in that cage you do whatever you need to…

It sounds more like they didn't follow the specific way bosh requires you to use their HW. I highly double VW or others would use Bosh if hacks are required to get them to work.

Re: Former Tesla Firmware Engineer Discusses the System

#189

Earlier quoted context omitted.

> This application was responsible for practically everything that ran the factory: inventory, supply chain management, cost analysis, etc. They could have bought something off the shelf. Not sure what was the value in building everything from scratch

What like SAP? And then spend 10s of millions in customizing it for their needs and dealing with an arcane, unintuitive interface? I've seen this over and over again.

I understand SAP's business model: common core business logic code that helps your legal compliance, then lightly customized at great expense.

What I don't understand is why the UI sucks so very, very much every single time. And why it's so very, very slow. It seems like it has to be on purpose. Can anyone with insight explain it to me?

Re: Former Tesla Firmware Engineer Discusses the System

#190
post #59

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).

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.

Pretty much anything that actually needs hard realtime is very likely running on a dedicated MCU/FPGA/ASIC. Linux is vastly easier to use for everything else, though. Navigation or communication doesn't need hard realtime, for example.
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