Recently, I need to build a working ROM for Nexus 5 from LG (hammerhead, here-forth). There are variety of tutorials and guide all over the web on the general steps needed to compile AOSP from scratch, which I do not intend to repeat here. Instead, I'll mostly focus on how to make the data connection (3G/LTE) working on Sprint phones.

Django provides an friendly Object Relational Mapping (ORM) framework. In several of my data analysis projects, I used Django ORM to process millions of logcat data generated by hundreds of Android phones. Here are some of the experiences and tips that helps making the processing just a bit faster.

Recently, I studied how Android Wi-Fi subsystem works. I was more specifically interested to learn the scan behavior. The source code related to this is mainly in framework/base/wifi/java/android/net/wifi/ within AOSP source tree.

In doing OS161 assignments, if you don't know how to use GDB and how to use it efficiently, you're screwed, and will die very ugly. It's a very important skill to use GDB to identify what's wrong with your code. That's the first step towards to fix the bug.

In developing PhoneLab Conductor, I need to get various statistics about a installed package to determine if a app is actively used by participant. For example, for interactive apps, I'd like to know how many times the user launches the app, and how long user actively interact with the app. For background apps (e.g., data collection), I'd like to know how long the background service has been running.

Recently, I've been working on dynamic channel selection based on channel utilization. One problem I encountered is: how to switch both AP and devices' channel without interrupting existing TCP connection.

When working on OS161 system calls, you'll probably see a bunch of this error, especially you haven't implemented _exit syscall and try to do some basic user programs, e.g., p /bin/true.

Note, this problem has been fixed in OS/161 version 1.99.07.

In developing PhoneLab Conductor app, I need to provide user a way to give us feedback after applying OTA update. Although this feature was disabled in release, I thought it's worthwhile to record how to implement that functionality anyway.

I encountered this problem when trying to get the final grades for an course I TAed for this semester. There were 10 homework assignments throughout the semester, and we're supposed to only count the 8 highest grades. So, how to accomplish this in Google Spreadsheet?

This post shows how to install os161 toolchain, including bmake, sys161, etc. on your local machine.