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Showing posts from May, 2009

Manhattanhenge

Today is a geeky holiday: the particular celestial alignment called Manhattanhenge where the sun sets exactly in line with the Manhattan street grid, which is about 30 degrees off from perfect east-west orientation. This picture which is taken from 5th avenue, shows the sun setting at the end of 22nd Street. Not exactly at street level and somewhat before the astronomical time of sunset, since the mathematical horizon is obstructed the coastline of New Jersey in the background. Some more pictures on flickr from 23rd st and 22nd st .

Poor-man's Testing Cluster

One of the biggest problems in embedded software development is how to most effectively test while the final target hardware is either not built yet or is too rare, unwieldy or expensive to give every software developer unlimited and unrestricted access to. Typical approaches include software simulation of the target on some general purpose computer or to find some suitable stand-in for the final hardware platform. Simulation by running the target OS on another CPU architecture (e.g. PowerPC target on an Intel based PC) is inaccurate for some of the important differences between CPU architectures like endianness and memory alignment . Simulation including the target processor architecture can be very slow unless the speed difference between the target platform (e.g. a low powered mobile device) and the host platform (e.g. a standard desktop PC or server) is sufficiently large to make the experience usable for developers - e.g. for the Android emulator included in the SDK. The ofte

Submarine Mode

I understand that one of the Google's ulterior motives with Android is to promote a mobile experience where the user is always connected to the Internet and the G1 is pretty much built around that "always on" networking paradigm - including the special flat-rate data plans from T-Mobile. On the other hand, data services are not universally cheap yet everywhere in the world and it would be nice to give the user more control over the mobile data usage. Both current commercial Android phones (HTC G1/Dream and G2/Magic) have two types of radio for data usage: GPRS/EDGE/3G cellular data connection IEEE 802.11 WiFi wireless LAN interface Since the Wifi interface is faster and was not exactly invented with power saving mobile devices in mind, it is presumably more power hungry than the cellular interface. In the implementation on the G1, Android gives precedence to the Wifi connection if enabled and available when the phone is active - i.e. when the screen is on. Once the scre

Subversion & Trac (SDI 07 Part III)

In this episde of the series on creating a minimal software development infrastructure, we are dealing with the centerpiece of the solution: setting up Subversion as the version control system and Trac to provide a unified and integrated system for bug/issue tracking, collaborative document editing (wiki) and source control repository browsing as well as a platform for further integration and extension . All the necessary packages are already installed on the server as part of the previous episode . Assuming that our infrastructure server has a payload partition mounted under /data and our fictitious project is called "sdi07", we are setting up the disk space for our project as follows: mkdir /data/ mkdir /data/sdi07/svn mkdir /data/sdi07/trac To properly initialize the databases for svn and trac, we need to run the following commands, svnadmin create /data/sdi07/svn trac-admin /data/sdi07/trac initenv and answer a few basic questions for trac-admin . In particular we

Platform Setup (SDI 07 Part II)

In the last episode of this series , we have decided to use Gentoo Linux on a skimpy tabletop server as the platform for the software development infrastructure for our fictitious new project. True to the hardcore image of Gentoo, the installation process for the Gentoo bootstrap binary distribution is a bit spartan (as of 2007). Fortunately Sabayon Linux provides a Gentoo derived distribution with a live CD to check out hardware compatibility and a simple installation process targeted at desktop end-users. Ok, I desktop distribution is probably not optimal for a server, but I needed to get the base system up and running as painlessly as possible (which it did). Once the minimal base system is configured to connect to the local network and is ready for remote login by an admin user, we can start with the setup of the service infrastructure. Based on the list of the services we want to set up, this is the shopping list of additional packages, which we need to download from the port

Cupcake is out of the Oven

The new version of the Android platform - 1.5 "Cupcake" - is now being shipped with the new HTC Magic phone from Vodafone and is also already available for some versions of the HTC Dream/G1. Since an OS update in the field is aways a scary business - T-Mobile is likely going to take it slow to upgrade all of the reportedly over a million sold G1 phones. Cupcake seems to be a relatively minor major release - a few significant new features (on-screen keyboard, video), some UI face lift and some improvement behind the scenes (battery life, performance). For my own use, there are two features which have made the upgrade to Cupcake a big deal for me. The touch-screen virtual keyboard is the big one. I have never been a big fan of the G1's hybrid touch-screen plus keyboard design and the virtual keyboard is more than good enough for me. In fact it is a lot better, since I for small text input, work flow from touch-screen navigation to text entry and back is a lot quicke

Choosing the Operating System (SDI 07 part I)

For the first part of the discussion on how to set up a minimal software development infrastructure for a startup project , using only open-source software, we are looking at the lowest layer in the technology stack - hardware and operating system. The first obvious reason for choosing an operating system for this development support server would be familiarity. If there is a particular OS or distribution the administrator is most familiar and comfortable with - this should probably be the most significant argument for choosing it. At the time of this experiment, I did not have any recent experience with any particular OS for the last few years, so the choice would be based on what I could most likely set up most easily without much of a learning curve and where I could get help most easily when I run into problems. The most obvious choice for an open-source operating system at this point is Linux , which runs pretty much on anything with a CPU - including almost any commodity PC ha