Older blog entries for LaForge (starting at number 198)

OP25 project joins hosting on osmocom.org

Some days ago, I noticed that the famous OP25 project (a Free Software implementation of the APCO25 system, a digital trunked radio system) was no longer reachable on-line. It seems they were running this on a desktop PC in a university. As nobody in the project still seems to be at that university, a change in the network configuration had accidentally rendered the website unreachable.

After some quick e-mails, I offered to host them within the osmocom.org family of Free Software Projects for mobile communications. This is when op25.osmocom.org was created, and a full-site backup uploaded + installed.

I'm really happy that we were able to do a small part to help to make sure this valuable project remains accessible to interested parties in the signal processing and mobile communications field.

Syndicated 2012-01-25 01:00:00 from Harald Welte's blog

Having Fun with DHL Express!

This is what I got when tracking one of my inbound shipments:

It seems DHL is having fun bouncing the package back and forward between Hong Kong and Leipzig(Germany). So far, it started in HK, then arrived in Leipzig on January 8, went back to HK, back to Leipzig, back to HK, back to Leipzig and is currently allegedly again in Hong Kong _after_ succesfully passing German customs clearance on January 15.

For the TCP/IP nerds among the readers: I wonder when the TTL expires.

Syndicated 2012-01-17 01:00:00 from Harald Welte's blog

First assembled prototypes of osmo-e1-xcvr

I mentioned it briefly before: I've designed a small E1/T1/J1 transceiver board, which is going to be used for experimentally interfacing such a TDM line with microcontroller and/or FPGA. The name of this board is osmo-e1-xcvr.

The first prototype PCBs have arrived yesterday, and despite lots of other more important work I couldn't resist but to actually solder some of the units. The result can be seen here:

I don't have time to do anything beyond very basic testing right now, but so far the boards seem to be doing fine. Now we need a driver for the transceiver chip, and connect its control interface over SPI to some microcontroller (likely sam7s/sam3s/sam3u in my case). The actual serial bitstream will end up at the SSC peripheral of the controller.

Syndicated 2012-01-14 01:00:00 from Harald Welte's blog

OsmoSDR status update

It's already two weeks since my last post mentioning OsmoSDR only very briefly. By now, OsmoSDR is fully public and you can read all about it on the http://sdr.osmocom.org/ website.

Specifically, the website includes Schematics, and one of my colorful block diagrams. I am a text guy and really hate to work with graphics, but the block diagram of the Calypso has helped a lot in the context of making people understand OsmocomBB, so I tried again for OsmoSDR:

So as you can see, it is a very simple, straight-forward design with a chip tuner, direct I/Q down-conversion, ADC for differential I and Q signals as well as a small FPGA for basic filtering and serial format conversion, followed by a Atmel SAM3U microcontroller (Cortex-M3, high speed USB).

And yes, it's receive only. However, it has a stacking connector for later addition of a transmit daughter-board which may eventually follow later in 2012.

So what is this OsmoSDR going to be used for? Well, for receiving any kind of signals between 64 MHz and 1700 MHz (possibly up to 1800 MHz, untested). We don't build it for a specific application, but we simply thought that for many applications a member of the USRP family is expensive overkill, and the FCDP has this arbitrary restriction at 96 kHz sampling frequency.

Please note that while I may be the only OsmoSDR developer that blogs about this project, it is very much a team effort and I'm only a minor part of that team. Apart from selecting the SAM3U, writing firmware and drivers for it as well as some discussions early on in the project, I didn't have any involvement in the Hardware design. Those credits go to Christian Daniel and Stefan Reimann.

So where do we stand? There are 5 prototypes of the first generation, they look like this:

There are some smaller hardware issues that were easy to work around, but one bigger problem related to the fact that the Si570 programmable oscillator output levels didn't match quite with what the FPGA clock input requires.

There will be a second generation board fixing this and other problems, and hopefully we'll see some progress in the weeks to come.

Firmware-wise, the code is currently scattered over a couple of different repositories, but I'm going to consolidate that soon. If you've worked with OpenPCD or SIMtrace, you will find some similarities: We split the flash of the controller into two partitions: One for the DFU bootloader, and one for the application code. You can then use the USB DFU (Device Firmware Upgrade) standard to quickly update the actual firmware of the device, without having to resort to jumpers or un-plugging and re-plugging of the hardware.

This also meant that I had to re-implement the old sam7dfu code for the SAM3U, which has considerable differences in the USB peripheral, cpu core, board startup code, etc. So it's really a reimplementation than a port. The good news is that I tried to make it as general as possible and integrate it with at91lib, Atmels reference code. So it should be easier to use it with other Atmel SoCs like the sam3s which I want to use e.g. in SIMtrace v2.

Syndicated 2012-01-10 01:00:00 from Harald Welte's blog

HTCs delays in releasing Linux source code are unacceptable

The Taiwanese smart phone maker HTC is widely known to be delaying its Linux kernel source code releases of their Android products. Initially, this has been described to to the requirement for source code review, and making sure that no proprietary portions are ending up in the release.

While the point is sort-of moot from the beginning (there should be no proprietary portions inside the Linux kernel for a product that wants to avoid entering any legal grey zone in the first place), I was willing to accept/tolerate it for some time.

At one point more than one year ago, gpl-violations.org actually had the opportunity to speak in person to senior HTC staff about this. I made it very clear that this delay is not acceptable, and that they should quickly fix their processes in order to make sure they reduce that delay, eventually down to zero.

Recently, I received news that the opposite is happening. HTC still has the same delays, and they are now actually claiming that even a 120 days delay is in compliance with the license.

I do think neither the paying HTC customers, nor tha Free Software community as a whole have to tolerate those delays. It is true that the GPLv2 doesn't list a deadline until when the source code has to be provided, but it is at the same also very clear what the license wants: To enable people to study the program source code. Especially in todays rapid smart phone product cycles, 120 days is a very long time.

So I hereby declare my patience has ended here. I am determined to bring those outrageous delays to an end. This will be one of my new year resolutions for 2012: Use whatever means possible to make HTC understand that this is not how you can treat Free Software, the community, its customers, the GPL and in the end, copyright itself.

Syndicated 2011-12-24 01:00:00 from Harald Welte's blog

More "bare iron" development: OsmoSDR, osmo-e1-xcvr and SIM bank

I'm currently quite excited to be doing more bare iron programming as well as actual electrical engineering work again.

There's actually not just one project I'm working on, but a variety of them:

  • OsmoSDR - an upcoming small form-factor, inexpensive USB SDR. Not big and expensive like USRP or real "professional" solutions, but also not as weak as the ultra-narrow-band funcube dongle. I wasn't involved in the hardware design, but have volunteered to take care of the firmware development for the Atmel SAM3U micro-controller inside.
  • osmo-e1-xcvr - a relatively simple circuit board containing the magnetics, LIU, clock generation and transceiver for E1/T1/J1 lines. The idea here is to have a solution for the analog part, as well as HDB3/B8ZS/AMI encoding, which can then be attached to any FPGA, CPLD or micro-controller development board. It exposes SPI for controlling the transceiver, and a synchronous serial bit-stream for Rx and Tx.
  • unnamed sim-bank project - here the goal is to find a cheap solution to attach a large number of SIM cards to either a PC or directly to Ethernet. This can be very useful for testing, where you host your sim cards in a centralized location and can borrow them to remote users/devices over TCP/IP. There are commercial devices available for this, but they are quite expensive (like 1700 USD for 32 card device) and intended to be used with some proprietary windows software (who wants that?!?).

In the latter two projects I'm also doing the component selection, schematics design and PCB layout. One project with KiCAD, the other in EAGLE, as I really want to get first-hand experience of the usability of Free vs. proprietary EDA tools. I'd love to also evaluate Altium Designer, but they are still windows-only, and that would just make life way too difficult for me.

The projects will be duly announced soon, and they are all intended to be Open Hardware designs with Free Software. We'll probably also make all of them available at shop.sysmocom.de, too.

Syndicated 2011-12-23 01:00:00 from Harald Welte's blog

Back home after successful KOSS Legal Conference

The first incarnation of the KOSS Legal Conference was a big success. There were many participants from a variety of backgrounds, such as

  • Independent Korean legal experts
  • Legal scholars from Korean law schools
  • International legal experts (e.g. Till Jaeger, Carlo Piana, etc.)
  • Representatives from the major Korean IT industry
  • Representatives of the community organizations like FSFE
  • Independent technical experts like Armijn Hemel and myself

The discussions have been a big success, with significant participation from the floor. There are many events that I attended where it was hard to actually get any participation from the audience - but the KOSS Law conference was definitely not one of them. Some of the questions were easy to respond to, some other questions really tackled the difficult issues in Free Software License Compliance.

What was clear to see from the Industry participants: FOSS License Compliance has become an important topic in the last couple of years: One the one hand as a result of virtually no TV set / mobile phone / PMP or other device running without Linux or other FOSS. On the other hand, I'm sure that the enforcement efforts of gpl-violations.org and the SFLC also have had significant impact on that.

What I personally find important is that compliance is only considered as part of the overall FOSS picture. Complying with the license text is the minimum that companies involved with FOSS should do. Rather, they should look beyond mere compliance and consider the benefit of engaging more actively with the community, contribute code back upstream/mainline and really becoming a first-class citizen of the Free Software world.

As a big surprise to everyone, Jim Zemlin of the Linux Foundation made a surprise visit towards the end of the second day of the conference.

Many thanks to the KOSS Law center for bringing this together and organizing such an event. Thanks also to the Korean NIPA (National IT Industry Promotion Agency) and the FSFE for their support of the event.

Syndicated 2011-11-28 01:00:00 from Harald Welte's blog

Some thoughts on the Erlang User Conference 2011

It seems I'm really getting too lazy to update this blog more frequently, which is a pity. Last week I was in Stockholm attending the Erlang User Conference 2011. This was the first Erlang conference I ever went to, and it was the first conference in many, many years where I was not speaking but merely a normal attendee.

Some of the readers of this blog will already have noticed my microblogging updates on identi.ca and Twitter that I made during the conference. They were not overly excited about the conference. Let me write some more details here. I have no idea how many technical conferences I have attended, but I am typically speaking at something like 10 to 14 every year, which I believe qualifies me as a "professional conference participant" ;)

Let me start with some positive feedback: There have been excellent and technical presentations, particularly by Kostis Sagonas (PropEr), Melinda Toth (Change impact analysis) and also the talk on Hashes/Frames/Structs as new built-in Erlang data types by Kenneth Lundin.

However, apart from those, i have quite a bit of criticism:

  • Some presentations ended way ahead of their schedule.
    This is a pity, as it means that some hundred-odd highly paid software developers are then sitting in a room and wasting time. If you hold a presentation at a conference, you should make sure that this time is used in the most efficient way. If you have been allocated a 45 minute slot, please don't make a 15 minute presentation + 5 minute questions session. That's not what the audience expects!
  • Keynote presentation by Ulf Wiger contained lots of hot air
    If I go to a technical conference aimed at Erlang users (i.e. software developers who write programs using the Erlang language, libraries and runtime system), then I expect it to be loaded with brilliant, technical content. I want to get excited about new developments, Erlang software projects, etc. The last thing that I'd want is having a real Erlang guru on stage talking about superficial, trivial aspects of embedded computing. Of course I respect the commercial decision of Ulf and/or Erlang Solutions to try to create a market for Erlang in the embedded sphere. But what is the technical relevance of this to the Erlang community? Ulf did not talk about great new schemes of optimizing the Erlang VM for battery-powered CPUs, or how he has extended powertop to give function or line-level accuracy on which of your Erlang code lines burn most CPU cycles or cause the highest number of CPU wake-ups from low power mode. That would have been exciting.
  • Erlang/OTP Road-map presentation without much technical details
    When I see a slide with "Some SCTP improvements" then I want to see what exactly are those improvements. I think there was more than enough time to go into more details, if Kenneth would have spoken faster and put more content into the available time. Once again, the audience is a room full of intelligent, highly-paid professional software engineers. If you get their attention for whatever amount of time, I believe you should pack it as full with information as possible, rather than bore them with slowly and carefully reading each line from a slide...
  • No Internet available at the Tutorials Can you believe it? In 2011, a technical conference aimed at software developers hosts tutorials inside a facility owned by one of the largest communications equipment suppliers (Ericsson) and then there is no provision for Internet access. It's really ironic, especially since at least some of the tutorial trainers expected the attendees would be able to clone git repositories on their laptops during the workshops.

In my hallway conversations with other attendees (who also have a background outside of Erlang and are more familiar with other conferences in the FOSS community), they independently observed those very same issues and agreed with my assessment.

All in all, the conference was a good trigger for me to finally sit down and start to use dialyzer on the various Osmcoom Erlang-language projects such as osmo_ss7, osmo_sscp and signerl. I'm already adding type specifications all over the code and am looking forward to soon starting with some PropEr test cases in the next couple of days.

Syndicated 2011-11-08 01:00:00 from Harald Welte's blog

Going to attend Korean FOSS legal conference

Recently I had been invited by the Korean Open Source Software (KOSS) Law Center to attend their 2011 KOSS conference scheduled for November 17 and 18 in Seoul, Korea.

This conference is organized by the KOSS Law Center with support by the Korean Government (National IT Industry Promotion Agency). Its primary purpose is to share best practises in terms of FOSS licensing, license compliance but also FOSS community interaction within the Korean IT industry and the public sector.

I'm happy to present on Beyond Legal Compliance - Embracing the FOSS community, where I will outline that the primary focus should not be on to-the-letter legal compliance, but to a proactive way of interacting with the FOSS community. After all, collaborative development is what FOSS is all about...

However, due to a schedule conflict with the DeepSec 2011 conference in Vienna (where I'm giving a two-day GSM security workshop), I'm only able to attend the second day of the KOSS conference.

The speaker line-up for the KOSS conference is quite impressive, and it includes Karsten Gerloff (FSFE), Till Jaeger (JBB), Carlo Piana (FSFE), Keith Bergelt (OIN), Armijn Hemel (gpl-violations.org/Tjaldur) and others.

Unfortunately there seems to be no homepage, at least none with an English language title that Google would be able to find. Carlo Piana has mentioned the event in his blog four days ago.

Syndicated 2011-11-08 01:00:00 from Harald Welte's blog

Upcoming GSM Security Training at DeepSec

Dieter Spaar and I will be holding yet another GSM security training on November 15/16 at this years DeepSec conference in Vienna.

We have been giving a series of successful GSM Security trainings in-house at various operators, as well as at a variety of conferences during the last couple of years. If you want to beef up your knowledge on the detailed inner workings of mobile networks, with a specific focus on security related aspects, this training might be a great opportunity.

You can register here. Unfortunately the Early Bird discount has already expired, but you still have a chance to book before November 2nd, after which a late booking fee will apply.

Syndicated 2011-10-17 02:00:00 from Harald Welte's blog

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