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Posts tagged ‘linux’

7
May

Cross-compiling for Raspberry Pi on Ubuntu

RaspberryPi Logo

While the Raspberry Pi 2 has four cores to churn through code, it still takes longer to compile than on most workstations and laptops. If you are feeling adventurous, you can try cross-compiling which has become easier to set up and get working.

Cross-compiling is when binaries created are for another target architecture than the one you are compiling on. This kind of set up is very typical when creating Android applications. The end result is that you can take the resulting binary and place on its target platform, and it will run there.

There are even tricks to getting the cross-compiled binary to also run on your native system!

In this guide, I’ll walk you through:

  • Setting up a cross-compile toolchain in Ubuntu (15.04 Vivid)
  • Setting up the proper exports
  • Compiling a test program for your native and target armhf platform
  • Compiling the latest Raspberry Pi 2 kernel with VC4 support.

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3
Oct

Wireless BCM4312 with the 3.10, 3.11, 3.12 and 3.13 kernels

Broadcom Chipset BCM4312
The hybrid driver from Broadcom was updated again in September (2013) with all the previous patches and a few other fixes as well. This brings them up to support linux kernel 3.9, which is very much welcome.

Sadly it breaks again with >= 3.10 with many warnings and errors which isn’t good considering that Ubuntu (13.10) Saucy Salamander is about to be released.

We do have a patch for you though that gets us working again up to the 3.11 kernel.

Chipsets supported by “Broadcom’s IEEE 802.11a/b/g/n hybrid Linux® device driver” are: BCM4311, BCM4312, BCM4313, BCM4321, BCM4322, BCM43224, BCM43225, BCM43227 and BCM43228.

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23
Jun

Worldsynth 0.11.0 released

Rivers

Worldsynth version 0.11.0 is released and can be found on github.

In this release we’ve added an additional algorithm for heightmap generation based on Ken Perlin‘s work in noise generation. We decoupled the sea-level to be configurable based on percentage, which in addition to masks we can now create islands. You can also save your world and open it up later since we use pytables to store our settings, metadata and our data in an open hdf5 format. You can also export your heightmap in 16-bit PNG greyscale or even import from a wide array of images formats as a heightmap. Importing from an image creates a 16-bit precision greyscale heightmap. In addition to this, one commenter ask about Python3 support, well now you have it.

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7
Mar

Worldsynth 0.10.0 released

Rivers

Worldsynth version 0.10.0 is released and can be found on github. This is our first “official” release in which the result should work, out of the box, with a usable and familiar GUI instead of the pygame environment. This is provided by Qt4 via PySide. We have even tested Worldsynth on Windows XP to validate that it is indeed cross platform.

As for 0.11.0, we are looking to unlock size of terrain to be of any variable width and height instead of the basic power of two. We are also investigating fluvial erosion.

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5
Mar

Latency simulation over long fat network

World NetworkOne of our clients asked us how we handle latency, and not just a few ms across racks but 2 and even 3 digit ms latency that indicates geographically separate locations across continents, not just a country. Not only that, the “pipes” involved are 10Gbps and we had to fill them. We have the theories and made models of how it would work. We perhaps might not be able to fill a 10Gbps fully with one stream, we could fill it with multiple streams but we had to validate this conclusion.

The question now becomes, how do we test this. We’ve done our research and there are only a few commercial solutions available like the Netropy 10G2 which is a 4 port, 2 lane hardware latency simulator for $30,000 new. Not only is that outside my budget, it is still limited to simulating 2 10Gbps pipes while we need at least 3 lanes (6 ports) and possibility to expand to more as necessary. We decided it was cheaper in terms of total cost to put the research into creating our own Latency Simulator.

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