Android Tether - When the Linux Laptop won't connect to WiFi but the Phone does

Linux users and the age old WiFi problem

A Linux die-hard, who'd rather distro-hop, than run any non-Linux based OS. After spending hours trying to figure it out, managed to get the problematic WiFi module to work with the home WiFi router. The laptop connects reliably to the Internet. Life is bliss. Or it is, until the fateful visit with the laptop to a friends or relative's place, a hotel room, or a local coffee shop, that has graciously allowed its patrons to use the Internet connection over WiFi, and the Laptop refuses to connect to the WiFi.

For best impact read the above again, this time in Rod Sterling's voice, like the opening from "The Twilight Zone".

Those familiar with this scenario can feel the frustration one goes through in this situation. I've gone through it many times over the years, and recently, my wife had to as well. The biggest cause for this is that, majority of WiFi modules that are packaged with laptops these days, come with little or no manufacturer support under Linux. That is the unfortunate state of WiFi networking under Linux.

For situations like this, I started carrying with me a USB WiFi module known to work under Linux, as a fail-safe. I sacrifice bandwidth for reliability and it has proved useful over the years. The flip side of this was that, the Android phones I've used over the years, always connected successfully to almost any WiFi network, and I could reliably access Internet over them.

The irony of the situation was that, the solution to my problem was in my pocket all this time, if only I had cared to check it there.  

Android Phone comes to the rescue

Almost all modern Android phones natively provide multiple forms of tethering options: WiFi tethering, USB tethering, and Bluetooth tethering. The good news is, some of these options could come in handy when faced with the WiFi connectivity problems.

WiFi Tethering

WiFi Tethering allows you to share your phone's data connection (3g, 4g, LTE, etc.) with computers that are within range, over WiFi. It transforms your phone into a WiFi Hotspot. The problem with this approach is, you are burning through your phone's data, which doesn't come cheap. Many carriers also impose additional charges to even allow data sharing over WiFi.

USB Tethering

This one took me by surprise. I had used USB tethering before; to share my phone's data connection with my laptops. Setting it up used to be more involved, requiring running a few commands, but newer Android phones have made it seamless to the point, where, it only requires one to check a checkbox on their phone, to activate it. What I hadn't thought of, or tested, earlier was that I could use USB tethering to even share the network that the phone was accessing over its WiFi connection. You do need a data capable USB cable for this to work. You'll know if your USB cable is data capable, if your laptop identifies your phone, and the phone identifies that it is connected to a computer.

Using this option, you'll be able to access your phone's Internet connection over a USB cable connected to you laptop. The connection speed will vary depending on your laptop and the phone capabilities. I was able to get nearly 15Mbps downloads and around 5.5Mbps uploads using this approach with my Nexus 5 phone.

Bluetooth Tethering

Modern laptops are shipping with WiFi modules that also have a Bluetooth radio. This allows the users to share files with other paired Bluetooth devices, as well as, do some other fancy Bluetooth things. For instance, I can pair my phone with my laptop over Bluetooth, and then all of my phone's sound notifications and other media playing, can be heard on my laptop. Another thing you can do over Bluetooth is share the Internet connection.

Like the earlier two options, you can extend your phone's data connection to the paired device. You may incur additional charges, but it is good to know you have that as an option. You could also, like with the USB tethering option, share your phone's WiFi network connection over to the paired devices - in this case, your Bluetooth enabled laptop.

Don't expect phenomenal speeds. This is Bluetooth we are talking about. My TWC Internet connection clocks nearly 20Mbps over WiFi. But when tethered over my phone's Bluetooth, it drops to mere 0.6Mbps. It's still better than your laptop's WiFi if it doesn't connect at all.

Initial issues with Bluetooth Networking

One issue I ran into, while attempting to setup Bluetooth tethering, was that, while the laptop identified the phone's Bluetooth network, and I could transfer files back and forth over Bluetooth, I wasn't able to connect to the Bluetooth network on my phone. Network Manager would show "configuring network interface" message, but always failed to connect.

I later realized that somehow the default configuration of the Bluetooth pair on my phone was interfering with this. The paired connection on my phone, for the laptop, did not expose "Internet Connection Sharing", as an option. I only saw "Media audio" and "Contact sharing", and both were checked. When I unchecked "Media audio" and tried to connect to the Bluetooth network "Nexus 5 Network" from my laptop, I was able to connect to the network. Checking the paired connection's option again on my phone revealed the a new checkbox option, "Internet Connection Sharing", which was already checked.

The Verdict

If you are on the go, with a laptop containing an unreliable WiFi module, you do have options. As long as you have an Android phone (only tested with an Android phone) and a USB data cable or a Bluetooth module for you laptop, you'll be able to stay connected. Of the two, USB tethering offers superior connections speeds, but Bluetooth tether offers yet another fail-safe in case you don't have a data capable USB cable with you. While you may not be able to reliably stream videos from YouTube or Netflix over Bluetooth, as with everything else Linux, it is yet another option.

A 2-in-1 laptop that just works under Linux: Dell Inspiron 13 7000 Series i7347

For quite some time, I've felt the need for an x86 tablet computer that I could carry with me when I was away from my main workstation. This need became a necessity when I started travelling for business, and while my trusty Bonobo Extreme, from System76, was everything I ever needed for a computer to be, it was also a little too bulky and heavy, which made it almost impractical to operate in tight spaces like in a car - while not driving, of course - and in planes. I knew that I needed something that was modern with a tight form factor like that of a Tablet, yet full featured, unlike many Tablets. 

The ideal tablet computer needed to be cost effective and with known compatibility under Linux 32bit and 64bit. I had considered buying the Surface or the Transformer earlier, but since this was going to be a companion computer and not the primary one, and I needed offline storage to install all my software for when I was on the go, the Surface didn't have enough storage or compatibility to just justify the cost, and in addition to the lack of sufficient storage, the Transformer wasn't powerful enough for my needs.

I discovered Dell Inspiron 13 7000 Series i7347 while researching 2-in-1 laptops on Amazon. After spending time researching it, it seemed like it was created with my needs in mind. The additional $100 off the sticker price of the Dell's original $599 made it an even more attractive purchase I could not afford to miss. I was a purchase I did not regret making.

The laptop is very slick and professional looking, which works great, since I intend to take it with me on my business and family trips instead of my more powerful, yet bulky, 17 inch Bonobo Extreme Laptop/Workstation. The hinges on the Inspiron are very sturdy and the laptop easily folds into a tablet. The touchscreen is very responsive. With a 500 GB hard disk at my disposal, I am able to use all my office productivity applications, as well as, software development tools and related services, without any difficulty. Now granted that this model is not an i7 or even an i5, but neither is it an Atom or ARM based. It provides a full computing experience with enough horsepower for smoother operation and functioning.

Installing Linux on it was a breeze. Almost everything worked right out of the box, and the only hiccup under Linux was, the not-so-well supported Wireless/Bluetooth module with Broadcom chipset. However, with little research, I was able to find Intel's Dual Band AC 7260 module, with the proper form factor, that was compatible and well supported under Linux. A version of that module, 7265, is also listed in Dell's specifications document for this laptop as an option. I suppose, if I had bought this directly from Dell, I might have been able to choose the Intel over the Dell Wifi module.

I also made the right call, when I decided to upgrade the WLAN module myself. The laptop is very easy to upgrade manually. The HDD, the RAM, the battery, and the WLAN module, among other things, are easily accessible, once you unscrew the base lid. On their website, Dell provides a Service Repair guide for this model, which provided all the necessary steps needed to help with the hardware upgrade, and that has only boosted my confidence in this machine and it's quality.

I am very happy with the purchase and would recommend it to anyone who intends to run Linux on it.

The 2-in-1 can be purchased from Amazon using the link below.

Note: there are two form factors the Wifi module is available under. You are looking for the smaller of the two.

7260NGW Intel® Dual Band Wireless-AC 7260 802.11ac, Dual Band, 2x2 Wi-Fi + Bluetooth 4.0

The Wifi Module can be purchased from Amazon using the link below. 

Thank you for reading and I hope you enjoyed the article.

How I learned to program in Scala: The Nexus 5 experiment

Few months back I broke up my long term affair with Mono and I started looking into the the Play Framework from TypeSafe as a replacement stack.

Through Play Framework, I discovered Scala and the wonders of functional programming. My interest grew even deeper when I installed Scala on my laptop and tried some example code in the REPL tool (think Scala interactive shell).

However, I found very soon that I was not able to dedicate enough time during the week to learning Scala due to my full time day job doing .Net development.

Something had to be done.

I thought, I have this wonderfully powerful device on me all the time - my Nexus 5. Surely, I should be able to put it to use to help me spend more time with Scala. So began the experiment.

I rooted my Nexus 5, installed "Linux Deploy" from Google Play Store and installed a chroot Arch Linux environment. I also installed JuiceSSH client and a VNC viewer application. I already had "Terminal IDE" installed which comes with a great android keyboard geared towards software development on Android.

The last piece to the puzzle, I bought a $25 ANKER bluetooth keyboard compatible with my Nexus 5.

I fired up the Arch chroot on my phone, downloaded tmux and vim using pacman and oracle java 7 packages from AUR (some PKGBUILD tweeking was needed).

Then I installed TypeSafe Activator from AUR. I also downloaded vim plugins like vim-scala and CtrlP which proved to be of great help.

It worked!!!

Using the setup described above, I was able to not only learn how to program Scala, I am also able to write software using Play Framework. I can test the same on my phone's browser. The code is backed up on github and I can work on the same codebase from anywhere - as long as I have my Nexus 5 and data connection.

And after the recent KitKat update with Cast Screen - I am able to cast my phone's screen to my big screen HD TV over ChromeCast. This solves the issue of developing on the relatively small Nexus 5 screen.

This experience has made me appreciate VIM, TMUX, and the terminal in general at a whole new level. Even when on my laptop, I now find myself doing more and more coding in VIM instead of IntelliJ.

Think about it, you can now get a decent android box or even a phone, and with a setup similar to what I described, have an almost full fledged development environment. Rich graphical applications can be written in Scala using Swing (sigh) and possibly other graphical toolkits and can be tested within the Arch (or other Linux distro) chroot using VNC.

Side note about Oracle Java instead of OpenJDK: I went with Oracle Java instead of OpenJDK due to an "issue" with OpenJDK on arm chips. Its something to do with JVM running in "mixed mode".

CloudNotes - New project - using the Play Framework

I recently came across the Play Framework and decided to take it for a spin. Needless to say I was amazed. I've decided to use it instead of .Net/Mono on a new project I've recently started work on.

The project is called CloudNotes. The goal of the project is to create a web-based collaborative notes taking and sharing application that is accessible from all platforms. As mentioned above, it'll be built use the Play Framework. I've chosen MongoDB as the database backend for this. LessCss, CoffeeScript, and jQuery, all of which come packaged as part of Play Framework, will be used extensively.

Currently, the application features:

1. Create and share notes using a web interface
2. Notes dimension and position on screen are stored along with notes - think web based collaborative brainstorming tool
3. GoogleDocs like collaborative editing of notes, although not yet realtime.

Features, I hope to develop into the application in the coming weeks:

1. User authentication
2. Access Control List on Notes and entries
3. Realtime interface with AJAX calls (currently causes full postbacks)
4. Mobile and desktop clients
5. Items reordering
6. Checklist module

The source code is hosted on github and licensed under GPL v2.

Once complete, I'll probably host a demo on a DigitalOcean droplet.

DigitalOcean offers cloud hosting for as low as $5/month or $0.007/hr for dedicated server with:

• 512MB Memory
• 1 Core Processor
• 20GB SSD Disk
• 1TB Transfer
• Additional bandwidth transfer is only 2¢ per GB

Update 1 - Progress so far - IrrlichtDotNet - .Net library for irrlicht that works under Linux

For original article, please go to this article.

After I made the declaration of starting this project on irrlicht forums, roxaz from the forums expressed interest in the project and immediately forked it on github. We bounced around ideas and while I won't yet merge all of his modifications into my repo, I did like many of this ideas and implemented them after tweaking them to fit in with my code. The ideas that I implemented from his repo are:

1. folder reorganization
2. a python script that refreshes the CS project file with all the SWIG generated cs files
3. make.sh file to automate many initial steps

I also spent some time getting myself more familiar with SWIG typemaps and was able to map irr::core::stringc to System.String for almost all instances. These originally got translated to a SWIG generated generic wrapper which wasn't any useful unless you created a companion helper class in C++ to handle the translation both ways between irr::core::stringc and char *, which gets mapped correctly to System.String. Once all occurrences of irr::core::stringc are mapped to System.String, helper class won't be necessary any more. I will also attempt to deploy more typemaps to handle other such mappings in IrrlichtDotNet project.

Linux compatible .Net bindings for irrLicht using SWIG

Ever since I tried IrrLicht, an Open Source 3d Graphics library, I fell in love with it. It is a C++ library and my C++ isn't as good as I'd like it to be and I am more comfortable with C# under .Net.

Since IrrLicht is open source, I figured, someone might have written an .Net binding for it, and I was correct. A few such bindings do exist, although, they are truly only .Net bindings for IrrLicht for Windows platform only.
I also attempted to use MonoGame, which is known to work under Linux, but without any success.

A few days ago, while researching an unrelated subject, I stumbled across SWIG. SWIG stands for Simple Wrapper and Interface Generator. It is used when you want write wrappers to your C/C++ code for other languages. It also happens to support C#. So I decided to give it SWIG a swing and initial results were more than promising.

I decided to test it but exposing the Main method of my C++ test code written to try IrrLicht and called it from a .Net application. It worked!
I decided to take a shot at generating a wrapper for IrrLicht itself. So far, using the bindings that I was able to create with SWIG, I have been able to create simple 3d scenes in C# code.

I've created a project on GitHub to create a Linux compatible .Net binding for IrrLicht using SWIG. The repo is at https://github.com/jimmy00784/IrrlichtDotNet.

Initially, much of the focus will be on creating a Linux centric binding. However, since SWIG is cross platform, if the community is interested in the effort, it could become more cross platform than that.

Day 2 - Porting nopCommerce to Linux - built in data storage

For some odd reason, I was now able to debug from within MonoDevelop again and that made me happy. Now that the Installation page loaded correctly, I decided to test the SqlServerCe built in data storage for nopCommerce. I provided the email and password, unchecked the "Create sample data" checkbox, selected the "Use built-in data storage (SQL Server Compact)" option and hit Install. Failed.

Setup failed: The requested feature is not implemented.

I set my breakpoint on the InstallController.cs and began walking through the code line by line to see where it had failed. I landed on SqlCeConnectionFactory.cs file line 41.

Contract.Requires(!string.IsNullOrWhiteSpace(providerInvariantName));

I tested the value of the providerInvariantName parameter to see if it was indeed null or whitespace, but it wasn't. For now I decided to comment this line and see if I could proceed. Same error. Examining the stack trace I found that Database.cs in the EntityFramework project had another Contract clause.

Contract.Requires(value != null);

And again, value wasn't null. It seemed like Contract clause wasn't behaving as designed. I decided to comment this one out as well. I found another one in EntityFramework, and then another one. After commenting out quiet a few of these over the next few trial runs, I decided to comment them all using Find and Replace. After fixing some compiler errors EntityFramework compiled without errors. Time to commit changes.

In next run, the application complained that it couldn't find SqlServerCe library. I noticed that Nop.Data project had an entry for System.Data.SqlServerCe.Entity.dll which had dependency issues under Linux. It appeared as though I couldn't get too far with SqlServerCe as the backend driver. I decided to give MS SQL Server a try instead.

In first try I got the familiar Feature Not Implemented error.

Setup failed: The requested feature is not implemented.

However, an empty database did get created. I did a search and commented Contract.Requires from the EntityFramework project. I also set a breakpoint on the FailFast  method in the Environment.cs core file which gets invoked when Contract clause failed.

Setup failed: The provider did not return a ProviderManifest instance.

Examining the stack trace hinted to this location: EntityFramework/Core/Common/DbProviderServices.cs:208.

There was also an inner exception being raised.

Invalid URI: The format of the URI could not be determined: System.Data.Resources.SqlClient.SqlProviderServices.ProviderManifest.xml

Further exploring down the stack trace took me to EntityFramework.SqlServer/SqlProviderManifest.cs:78 which passed a baseURI parameter. For some reason Mono didn't like the value that was being passed. I used an overloaded method that did not require baseURI to see if it'd let me proceed.

Setup failed: The requested feature is not implemented.

This was being raised from the EntityFramework.SqlServer project. I did another search and comment on Contract.Requires this time on the EntityFramework.SqlServer project.

System.StackOverflowException: The requested operation caused a stack overflow.

After another round of placing breakpoints and tracing through the code, I found that the stack overflow was being caused by EntityFramework/Core/Common/Utils/Memorizer.cs:71 when attempting to evaluate result.GetValue(). I surrounded it with a try catch and returned the default value of the generic TResult in case of an exception to see if it'd let me proceed.

Setup failed: An unexpected exception was thrown during validation of 'Name' when invoking System.ComponentModel.DataAnnotations.MaxLengthAttribute.IsValid. See the inner exception for details.

This was coming from EntityFramework/Internal/Validation/ValidationAttributeValidator.cs:75. Inner exception hinted of an unimplemented function.

IsValid(object value) has not been implemented by this class. The preferred entry point is GetValidationResult() and classes should override IsValid(object value, ValidationContext context).

In order to proceed, I forced a ValidationResult of Success.

Setup failed: The handle is invalid.

Reviewing the stack trace took me to EntityFramework/Core/Metadata/Edm/LightweightCodeGenerator.cs:193. Examining the code showed that CreatePropertyGetter was creating a dynamic method to map to the getter method of a property on an Entity. After some more trial and error, it became apparent that while the Type handle was mapping correctly, the RuntimeMethodHandle held an invalid value. Fortunately, the getter method on a property has the naming convention of get_PropertyName. This could come in handy to boot strap this code to allow proceeding further. Time to commit changes and review the work.

I reviewed the database that was created by the application, and I see tables being created. This means that EntityFramework is facilitating table creation which is good news. This is a good stopping point for the day.

Conclusion thus far: SqlServerCe driver won't work under Linux, however, after some heavy tweaking and commenting of EntityFramework code, SqlServer driver does work, at least as far as creating tables.