Living in a Linux Embedded World

krow writes: "Embedded.com is running an article where the author is making some assumptions of Linux's use in the embedded markets based on the opinion of one consultant and the fact that Lineo had to lay off some people this year. It's still interesting reading though for some insight into a different world for Linux and there is a nice reference in the comments to the interview of Victor Yodaiken of RTLinux fame by by Kevin Fu on the ACM site."

Comments

Kada

[Apreche]

It's a pretty strange coincidence. Today I had to get information about a company for Professional Communications class. I went to the library, picked up an IT trade magazine, and went to the section about emerging companies in the new year. There is apparently a company called Kada Systems. That has created an extremely small JVM that can run very powerful applications on very small portable devices. Take that and your tiny linux kernel, and you're set.

Of course not

[bluGill]

Most embedded componants that I know of use an in house OS. Where I work we bought vxWorks, but we are seriously considering replacing it with something cheaper. Not linux, something we write in house. It turns out that most real time systems cannot afford the overhead of a OS. Sure we need something to deal with hardware, and schedualing, and if you have networking it is nice to have sockets are similear. In the end though, a OS gets in the way more then helps.

In our particular case we have a lot of code to jump out of interupt context and then back in every 15 seconds. That really hurts performance. (Yes, we often want to spend more then 15 seconds processing interupts, with out hardware it turns out to be a good idea, though I don't want to give away why) Of course the OS clocks get all screwed up when we do that.

Long Cycles

[nate1138]

Part of the issue may be that embedded systems have pretty long development cycles, compared to typical software apps of similar size and complexity. If your PC application doesn't work, you simply issue a new revision with fixes. Embedded systems are much more difficult to upgrade. I'm not talking about PDA's here, I'm talking about your set top boxes, industrial systems, data collection, etc. These systems cannot be easily patched. As a result, embedded linux development efforts take much more time to certify than those using RTOS's that have been around for years. Also, it is true that linux doesn't have a native method for doing hard-real-time events, there are add-ons, and it isn't the fault of linux developers, such a thing simply isn't needed for desktop and server OS's, but for running an industrial robot, a 10ms delay can be disastrous.

Why some developers are running from Linux

[dfeldman]

I used to work closely with a development team that made the transition from a proprietary (and, may I add, unmaintainable and unreliable) embedded OS to Linux. Though some of the concerns in the article did come up, especially speed and size issues, those didn't hurt us much. After all, we could afford a better processor and more memory with the money we saved on royalties and maintenance expenses - these were substantial.

Unfortunately, if the many features of Linux and the transition from assembler to C didn't hurt us, the licensing did. Things went very smoothly until we needed to make some big changes to the kernel to accomodate a newer version of our hardware. At that point, there was a schism in the group: some of the developers wanted to change the kernel and release the product without source (the "who would find out?" crowd) and the rest of us knew that Linux was not going to fit our needs anymore unless we wanted to give our work away to competitors.

Well, the "who would find out?" crowd won the first round, and because of release deadlines we "slipped" the kernel changes into the next version of the product. And nobody knew. Except one of us told the legal department about what happened and they became very agitated.

Now our software runs on embedded NetBSD. It wasn't quite as robust as embedded Linux but it works well and we really can't complain. Transitioning to a new OS took a lot of effort but it was a necessary evil. After all, we couldn't risk getting sued out of existence to save a little money.

But the question I draw from this is: why not relax the GPL restrictions a bit for embedded applications? It seems like this area of the market will never be dominated by Linux until companies can stop fretting about licensing problems and start concentrating on coding instead.

df

He's Right

[DrStrange]

Sorry to anyone who believes Linux is THE choice for everything, its not. As a real time embedded developer who has done some work on Linux device drivers I have yet to suggest Linux as an option when the OS choice has come up. I agree with the author when he cringes at some of the commentary in the Linux source code, I'm supposed to stake my name and my company's name on an OS with comments like: "/* This is a hack..." in the kernel? And say we do go with Linux and a problem with the OS comes up what should we do? Post to the linux-kernel mailing list and hope it gets fixed? Assign one of our developers to fix it? We don't hire OS programmers for the very reason that we buy our OS, we're DSP engineers. Most companies won't go with Linux because of the fact if something breaks they can't submit a bug report and withhold payment until it gets fixed.

I'm an avid Linux user at home but for fault-intolerant real time systems, I would feel a bit uneasy recommending Linux for an embedded system just yet. Once I go 6 months without a story on /. where a major fault has been introduced or missed in the Linux kernel I may rethink my opinion but until then I'll be suggesting that we buy our RTOS.

It's a matter of education

[Zero__Kelvin]

Like so many things in the computer world, there is a need for education in the Real-Time embedded arena. When I was at the Embedded Systems Conference - Boston 2001, Red Hat's CTO gave a presentation on Embedded Linux, and touted RTLinux as the up and coming 'official' Real Time approach. In a later discussion with him, we agreed what everyone seems be missing here ...

Most embedded systems are *NOT* hard real time systems. For those that are, there it the RTLinux wrapper that runs Linux as one of it's (lower priority) processes. Yet the people writing for sites like this have no clue and spread FUD, which the unfortunate reader often mistakes as factual.

Will Embedded Linux ever be popular? It all depends on if the Embedded Systems Engineers ever get properly educated as to what it can do, and how. The only real drawback is footprint size. If you need your embedded application to be small and run on 8-bit Microcontrollers, then Embedded Linux clearly isn't for you. However, for the vast majority of serious applications, Moore's law continues to make Embedded Linux a more and more viable solution if the Engineers start addressing the learning curve. Of course, first, they have to know that such an effort is worthwhile. With FUD like this article spreads, it will unfortunately be longer until people get it. No big surprise here. Almost everyhting worth while gets early adopters, goes on hiatus, and then comes back as the new latest and greatest thing that everyone always new was going to fly. You gotta love the cycles of life!

A better question

[AstroJetson]

Why didn't your company want to release the kernel mods back to the community? It's not like they were gonna make any money off them - they get paid for the embedded app, not the OS it runs on. I could understand if you were giving away something proprietary, but it doesn't seem to me that releasing those changes would have hurt your company one little bit. In fact, if you had released them, someone else might have come along and improved on your improvements.

Layoff-based reasoning.

[Syberghost]

Hey, didn't Dell lay some people off? Gee, Windows must be dying.

Didn't @Home go bankrupt? The Internet must be dying.

FedEx has a hiring freeze; oh, no, people must be using the Post Office more!

we should have a solution

[linuxlover]

This is exactly the issue I am considering aswell.

Lets say our company invents a device and plans to sell the device with Linux loaded terminal with Linux device driver. The hardware+software is our IP and we can't give it away. please don't lecture me of how everything should be free...etc. I know that, and I also like a roof above my head. Letting people download my driver for free from a FTP server doesn't quite pay my bills.

So the solution:
we need to have something like FSF or Linux Fund. If I want to keep my driver closed source say for 1 year then I pay a license fee for them (it can be a one time thing or royality based). The 'foundation' distributes the money as it see fit, funding developers, funding new projects..etc. After a year, I have 2 options
- release the source to kernel main tree and make it open. Now it doesn't matter as competitors can't abuse my work to overtake me.
- continue with closed source for another year and keep paying (may be revised) licese fee / royality.

This has best of both worlds
- I get to use a stable well maintained software (in this case Kernel). so I don't have to re-invent the wheel inhouse everytime.
- I keep my IP intact for a short period and at the same tiem paying for other developers efforts.

any one know any similar licences like this?

LinuxLover

Success story

[Snafoo]

I'm a junior engineer at a small company producing (a fairly killer, IMO) embedded-linux (ix86 atm, but that could change next release) device. Although the RT side of things is not my schtick -- I'm writing some custom web software and working on our in-house embedded-linux distro --- I *do* know that our RT guy is the biggest linux fanatic I know. He seems to have no problems using the RT stuff that's freely available for the linux kernel, and kernel-versus-license-wise, we're simply going to release the stuff we need to keep proprietary (FPGA drivers and firmware-adjustment/config stuff) as kernel module(s).

In fact, RT guy *regularly* slams anything that doesn't have adequate RT support, so I am left to assume that he deems to have a set of RT capabilities which is more than adequate. :)

We're a small company, and running (like everyone else) under some rather tight fiscal constraints.
AFAIK, linux is what is currently saving our collective bacon -- if we're going to compete with the economies of scale of the big boys (not to mention their 'Deep Pocket Error Correction Algorithm') we can't afford to license some proprietary OS or development environment and pass that cost on to our customers. We have to be clever; therefore, we use Linux.

(Aside: I wish I could provide more details, but really, I'm more of a CS geek. My ideal level of abstraction is somewhere just south of lisp and north of Java. Assembly makes me go *bew*bew*bew*bew* (imgine index finger oscillating in front of lip). )