mbed’s BSD B.S.?

Posted on Friday, May 3rd, 2013 in open source by Ian


A couple days ago mbed, the ARM platform with a silly online compiler, announced that it’s register abstraction layer would be released under an open source BSD license. Readers raised the point that this is only partly true. We hate it when open source is used as a publicity ploy with only partial code releases, even when friends do it. The major complaints seem to be:

  1. Registration is required to download
  2. Open source files are mixed into a single package that has a restrictive non-open source license. This license doesn’t allow porting to other platforms, a page out of Microchip’s playbook. Ugh.

Legalese iz hard, so this could definitely be an oversight by developers who care more about code releases than the technicalities of licensing.

Here’s what the community is saying:

…[a] single big CMSIS package is still provided (filename:, which includes both BSD-licensed and proprietary-licensed components.

The problem, as the initial messages says, is that user is given non-OpenSource, highly restrictive EULA to accept before downloading the complete package, with provisions in that EULA directly conflicting with BSD license.

Emilio Monti, mbed forum.

…Emilio specifically links: “We are distributing some of its components in the mbed SDK sources”. I clicked through and am finding non-BSD licensed code (example)…

“This file can be freely distributed within development tools that are supporting such ARM based processors.” That’s not BSD and not open source.

I would love to be proven wrong, but this looks like the second time mbed has made a BS announcement about being open source. Worse, DP has posted both announcements with a prominent OSI logo without verifying the claims. DP, you are part of the problem.

mossmann, via the comments. Criticism taken. We didn’t dig through the source before posting, but we’ll highlight the issue now.

If you want just the BSD licensed code, Paul uploaded it to github.


This entry was posted on Friday, May 3rd, 2013 at 2:54 am and is filed under open source. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

7 Responses to “mbed’s BSD B.S.?”

  1. mossmann says:

    Thanks for following up and taking criticism well, Ian. And let me add: other than that one thing, I enjoy your blog every day, use your hardware often, and am a big fan overall. :-)

  2. Ian says:

    My pleasure. Thanks for pointing it out. The last thing we want to do is encourage bad behavior.

  3. Kris Lee says:

    Mbed has been bullshit from the beginning. Fact that they are suggesting something restrictive like online compiler whose availability dependes on the goodwill of one company is anything but open.

  4. J. Peterson says:

    I’m disappointed to see the harsh criticism of mbed here, in particular the remark about the “silly” online compiler.

    I’ve used a fair number of embedded environments (Microchip, Renesas, Zilog, NEC, TI, Motorola, etc.). One of the most tedious aspects of all of those is installing, configuring and updating the development tools. It’s unproductive time down the drain, and hey, if you want to switch to a new computer or update Windows, you get to do it all over again. In fact, if you want to switch to Mac or Linux for development, you’re likely to be out of the game completely.

    With mbed, all that goes away – the experience is literally just log in and start coding. Overall I’ve found the quality and completeness of the mbed web-based tools easily on par with some of the best Windows-based environments provided by other vendors. And they’ve recently added one-click export to other toolchains (including the GNU compiler) so it’s easy to back up your work off-line. Its very clever and well implemented.

    I suppose if the success of your project really depends on a completely free source base, the licensing stuff may be an issue. But for a lot of projects (e.g., the one-off for the lab or that first prototype on the breadboard) those issues really aren’t relevant. Now, not being able to even look at the library source was an issue for debug and development, but the “open” that mbed recently provided solves that issue.

    As somebody who’s been a professional software developer for decades, I highly recommend mbed for anybody doing entry-level ARM development. (And I have no connection with mbed, NXP or ARP other than as satisfied customer).

    • Kris Lee says:

      You are right. It definitelly is not silly. It is quite smart actually. And evil. It shows the future where people are left with stupid screens.

  5. Rodger says:

    Not evil at all. Mbed people actually made programming ARM micros easy for non-geeks.

    And mbed doesn’t restrict you either. You want to use RowleyCrossworks or Atollic, etc that’s fine as well.

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