Power-cycling a USB port should be simple, right?
Every so often I happen to be involved in designing electronics equipment that's supposed to run reliably remotely in inaccessible locations,without any ability for "remote hands" to perform things like power-cycling or the like. I'm talking about really remote locations, possible with no but limited back-haul, and a very high cost of ever sending somebody there for remote maintenance.
Given that a lot of computer peripherals (chips, modules, ...) use USB these days, this is often some kind of an embedded ARM (rarely x86) SoM or SBC, which is hooked up to a custom board that contains a USB hub chip as well as a line of peripherals.
One...
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New MOnSter6502 updates, with video!
https://player.vimeo.com/video/217483777
It’s been a while since we’ve had an update to the MOnSter6502 project–we’ve been very busy getting the second revision ready. At the same time, I’ve been designing a simple yet powerful 6502-based computer that can operate at the slow clock speeds required by the MOnSter6502.
But before I go into detail about that, take a look at this video update. It’s one thing to see photos of the MOnSter6502, but the video really brings out just how awesome this thing is in person! (Shameless plug for Maker Faire Bay Area 2017 where you should come visit us.)
The MOnSter6502 runs up...
Overhyped Docker
Overhyped Docker missing the most basic features
I've always been extremely skeptical of suddenly emerging over-hyped technologies, particularly if they advertise to solve problems by adding yet another layer to systems that are already sufficiently complex themselves.
There are of course many issues with containers, ranging from replicated system libraries and the basic underlying statement that you're giving up on the system packet manager to properly deal with dependencies.
I'm also highly skeptical of FOSS projects that are primarily driven by one (VC funded?) company. Especially if their offering includes a so-called cloud service which they can stop to operate at any given point in time, or (more realistically) first...
OsmoDevCon 2017 Review
After the public user-oriented OsmoCon 2017, we also recently had the 6th incarnation of our annual contributors-only Osmocom Developer Conference: The OsmoDevCon 2017.
This is a much smaller group, typically about 20 people, and is limited to actual developers who have a past record of contributing to any of the many Osmocom projects.
We had a large number of presentation and discussions. In fact, so large that the schedule of talks extended from 10am to midnight on some days. While this is great, it also means that there was definitely too little time for more informal conversations, chatting or even actual work on code.
We also have such...
Book on Practical GPL Compliance
My former gpl-violations.org colleague Armijn Hemel and Shane Coughlan (former coordinator of the FSFE Legal Network) have written a book on practical GPL compliance issues.
I've read through it (in the bath tub of course, what better place to read technical literature), and I can agree wholeheartedly with its contents. For those who have been involved in GPL compliance engineering there shouldn't be much new - but for the vast majority of developers out there who have had little exposure to the bread-and-butter work of providing complete an corresponding source code, it makes an excellent introductory text.
The book focuses on compliance with GPLv2, which is probably not too surprising...
OsmoCon 2017 Review
It's already one week past the event, so I really have to sit down and write some rewview on the first public Osmocom Conference ever: OsmoCon 2017.
The event was a huge success, by all accounts.
We've not only been sold out, but we also had to turn down some last minute registrations due to the venue being beyond capacity (60 seats). People traveled from Japan, India, the US, Mexico and many other places to attend.
We've had an amazing audience ranging from commercial operators to community cellular operators to professional developers doing work relate to osmocom, academia, IT security crowds and last but not least enthusiasts/hobbyists, with whom the project[s]...
Making a bench PSU out of a cheap buck/boost module off the web
Modding a LTC3780 board to use different pots, toroidal transformer rewinding and a bit of bodging gone wrong.
Things you find when using SCTP on Linux
Observations on SCTP and Linux
When I was still doing Linux kernel work with netfilter/iptables in the early 2000's, I was somebody who actually regularly had a look at the new RFCs that came out. So I saw the SCTP RFCs, SIGTRAN RFCs, SIP and RTP, etc. all released during those years. I was quite happy to see that for new protocols like SCTP and later DCCP, Linux quickly received a mainline implementation.
Now most people won't have used SCTP so far, but it is a protocol used as transport layer in a lot of telecom protocols for more than a decade now. Virtually all...
SIGTRAN/SS7 stack in libosmo-sigtran merged to master
As I blogged in my blog post in Fabruary, I was working towards a more fully-featured SIGTRAN stack in the Osmocom (C-language) universe.
The trigger for this is the support of 3GPP compliant AoIP (with a BSSAP/SCCP/M3UA/SCTP protocol stacking), but it is of much more general nature.
The code has finally matured in my development branch(es) and is now ready for mainline inclusion. It's a series of about 77 (!) patches, some of which already are the squashed results of many more incremental development steps.
The result is as follows:
General SS7 core functions maintaining links, linksets and routes
xUA functionality for the various User Adaptations (currently SUA and M3UA...