The game of global whack-a-mole continues, and it does not favour those holding the mallets. tvrss.net, formerly my source for RSS feeds of torrents of my favourite TV shows, is likely down for good. You can search eztv.it for individual torrents directly, but why? showrss.karmorra.info is already up, and it’s even better than tvrss.net. Now I have one custom feed for all my shows, and it automatically filters out duplicates and resolutions I don’t want.
You are currently browsing the yearly archive for 2009.
Tags: htpc
When I starting using WordPress on tolaris.com, I noticed an innocuous link in the admin interface entitled “Turbo”. This feature uses Google Gears to speed up working with the blog, and to work offline (!) by storing data (html, images, javascript) in my firefox profile and running javascript in the background. Unfortunately, Google doesn’t release Gears for 64-bit architectures.
Today I discovered that someone has patched Gears to work with Firefox 64-bit, and released a precompiled installer. Warning: after installation, when Firefox restarts, you will see a warning that the plugin could not be installed (‘”Google Gears” could not be installed because it is not compatible with your Firefox build type (Linux_x86_64-gcc3). Please contact the author of this item about the problem.’). However, it is installed and works just fine. Unfortunately this message is repeated each time Firefox restarts.
I can now browse my admin page with Firefox in offline mode. Sniffing proves that not a byte is passing. Now I can write blog posts on planes, without having to use an offline text editor.
Update 2009-05-29: My old colleague from my days at Greenpeace, Niels Peen, now provides the latest version (5.21.0) with proper build tagging. So you will no longer see the warning about Linux_x86_64-gcc3 being the wrong build type. Thanks, Niels!
Update 2009-07-24: 5.31.0 and 5.32.0 are now available here, also with build instructions so you can do it yourself!
We use Quintech SRR2150 L-band switches at our teleports. These are simple devices for switching L-band inputs and outputs. The most common application for one is to switch inputs to a spectrum analyser. This allows me to use one spectrum analyser to monitor several inputs (multiple antennas, multiple polarisations on the same antenna, etc).
Quintech’s switches are pretty basic. They have a front control panel, an interactive shell accessible by serial or telnet, and a custom communications protocol over 9100/TCP. Quintech provide a basic Windows management application, but it is either rudimentary (version 1.0) or totally broken (version 2.06). Why not control it from the command line? Thankfully Quintech have fully documented their management protocol, and implementing it in Perl was a few hours’ work back in 2007.
As I mentioned in my last post, I now have a Home Theater PC (HTPC). Want to look under the hood?
I recently bought a Shuttle X27D to use as a Home Theater PC (HTPC). The reviews of this hardware run from disappointing to average, but I’m reasonably happy with it. It’s quiet (just one small fan for the GPU, and none for CPU, case, or power supply), uses little power (I measured it at 32 W in full operation), and the analog audio jack on the motherboard has no discernable noise in the audio stream (unlike my Dell Vostro 1500 laptop).
Unfortunately, the Intel 945G graphics processor can’t reliably handle 720p @24 frames video. I tested with a downloaded copy of Sita Sings the Blues, and it dropped frames as the animated fireworks exploded during the title sequence. It was fine with most of the rest of the film. Still, it means I’m likely to stick to upscaled 480p video. Which is far better for my bandwidth usage.
Naturally, I ran into some problems setting it up.
I recently posted about backporting packages with pbuilder. Someone asked about forward porting PHP4, which is a huge task. PHP4 is out of date, and the entire set of PHP4 libraries has a lot of build dependencies, including some packages you must build yourself. I’m not going to take you through the process of backporting PHP4. If you really need it, you can install php4-cgi and php4-* from Ubuntu dapper directly on hardy. But I will show you how to enable a local repository in pbuilder. This will allow you to build a package with pbuilder, and then use that package to satisfy any build-dependencies that other packages need.
Finally, finally, FINALLY! The Sun Java plugin now works on Firefox amd64 in native 64-bit. It has already been included in Ubuntu 9.04 Jaunty, but the packages work just fine on Hardy as well, and probably on Intrepid.
Just download and install the Jaunty versions of sun-java6-bin, sun-java6-jre, sun-java6-fonts, and sun-java6-plugin. Install them, and remove the old icedtea plugin if you have it:
sudo dpkg -i sun-java6-bin_6-13-1_amd64.deb sun-java6-fonts_6-13-1_all.deb sun-java6-jre_6-13-1_all.deb sun-java6-plugin_6-13-1_amd64.deb
sudo apt-get remove --purge icedtea-gcjwebplugin
Then restart Firefox and Sun java will load natively 64-bit. Check it:
tyler@baal:~$ java -version
java version "1.6.0_13" Java(TM) SE Runtime Environment (build 1.6.0_13-b03) Java HotSpot(TM) 64-Bit Server VM (build 11.3-b02, mixed mode)
I’ve included them in the repository.
Update 2009-07-16: A more recent version is now available in the hardy-updates repository. I have removed the above copy from my repo. Intrepid users should upgrade to jaunty anyway, but can still download packages directly.
In the satellite world we frequently work with the decibel scale. Decibels (dB) are a way of expressing the relative difference in signal strength between two sources. It is a logarithmic scale, so increasing numbers represent an exponentional increase in power. In simple terms, they are a convenient way of using addition instead of multiplication.
There are plenty of good places to understand decibels. I want to focus on how this helps us answer a few important questions in carrier sizing.
- I have two carriers, P1 and P2. What is the difference in power (Y) between them? Commonly this question appears as “Customer has capacity P1 and wants P2. How much additional power does he need to support the new carrier?”
- I have carrier P1 of a certain size, and Y dB margin (additional power available). How large can I make my new carrier P2? Or if Y is negative, how small?
I frequently need to package software for install on Ubuntu systems. If you manage only one server, don’t upgrade often, and don’t need to uninstall, then you may be happy with the ancient “untar, make, make install” method. But if you’re like me you prefer to create .deb packages and install those.
I run Ubuntu 8.04 “hardy” on my servers. Hardy is almost a year old now, and although it has up to date security fixes it no longer has the latest releases of software. This is fine for most purpose, but sometimes I want an updated version of some software and I’m willing to risk the slight chance that it has bugs.
The best traceroute tool around is mtr. The version in Hardy is 0.72, but Jaunty now has a package for 0.75. So let’s backport it with pbuilder.
Update 2012-05-16: These instructions have been superseded by a new version of this guide. Follow that document instead.
Update 2010-08-18: These instructions are still valid as of VirtualBox 3.2.8 and Ubuntu 10.04 “Lucid Lynx”. VirtualBox now creates a “vboxnet0” interface by default, but this is not a bridge.
I use VirtualBox every day. The satellite world is infested with bad Windows-based management tools that fail to run in Wine. So I often run those apps in a Windows virtual machine, safely sandboxed the way Windows belongs.
Note to hardware developers: if your network-based device does not have a standards-compliant HTTP interface, you lose. If it has a Windows-based management tool instead, you lose twice. I will buy your product only if I have no other choice.
I imagine running Windows apps is what 90% of VirtualBox users use it for, but it can do so much more than that. I also run several Linux-based VMs, and use them to test server configs, or even whole networks before rolling out the real thing. If you do this, you probably want to use more than the basic NAT networking that VirtualBox uses by default. For instance, wouldn’t it be nice to install an SSH server in the VM, minimise the VirtualBox GUI, and SSH in from a terminal just like you would a real server?
Tags: networking, virtualbox
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