Microsoft’s Windows Mobile, Apple’s iPhone, and RIM’s Blackberry

In the past week I’ve seen several post on the MSDN Smart Device forums asking essentially the same question.  Some one has developed (or will develop) a program for one platform (Windows Mobile, Blackberry, iPhone) and wants to make the program run on the other.  I’ve answered the questions as I’ve encountered them, but since it is a frequent question I decided to write a post about it so that I can refer people back to an answer as the question comes up.

What is a Platform?

A platform is a collection of functionality along with the methods for accessing that functionality provided to support an application. Traditionally platforms have been viewed as a combination of hardware and software; a software application would require a certain software platform (the operating system) running on a certain hardware platform (the physical computer with a certain processor).  While that definition is still applicable presently we also have what would be considered pure software platforms; a developer targeting a browser can target a specific web standard as their platform with little to no concern for the hardware on which it is run.  It is important to also note that platforms can be layered; one platform can exists on top of another. For mobile devices I can name 5 platforms; Windows Mobile, iPhone OS X, Blackberry, Android, and Symbian.  As I type this

How do I make this program developed on platform X run on platform Y.

Unfortunately in most cases the answer to this question is “you don’t.”  You will need to rewrite your application for the other platforms on which you need for it to run. What’s the workaround for this?  Well, as I mentioned in my definition for a platform, “platforms can be layered; one platform can exists on top of another.”  If you have two dissimilar platforms and if those two platforms can support the same software platform then you can target that common platform and end up with a single application that runs on multiple platforms.

Web browsers are going to be the most common platform that you can target.  But browser applications have their limitations (those limitations are diminishing).  The two most populate virtual machine platforms are .Net and Java, but you will find that presently different devices have different levels of support for these two platforms.

So What are you Saying

After reading the above you should be able to infer what I am about to conclude.  IF you need to run a single application for multiple platforms make it a web app and adapt it to the browsers (or browser standards) that you wish to support.  If it absolutely has to be a native application then you will not be able to create a single application that runs on Windows Mobile, iPhone, Symbian, Blackberry, and OS X.

/www.j2i.net.html

 

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.Net Micro Framework Development Board

The Windows Embeded Blog had a post about a .Net Micro framework development solution that cost under 100.00 USD. For the pricepoint and the functionality this is an incredible package!  I may have to pull out my notebooks for some of the automotive projects I wanted to do (I had been considering a Windows CE device for those projects but I think this package should be more than adaquate).  If you are interested you can grab one of these from GHI Electronics.

Update [2008-09-18 23:20 UTC] – feeling that this is such a power product I’ve already submitted an order for one for myself.

 

New Tilt Firmware Buggy?

The Tilt firmware update was welcomed with open arms.  I installed it, and after a few failed attempts I figured out how to prevent the bloatware from installing.   But the 6.1 firmware for the Tilt is not working as well as I had hoped.  The most annoying problem is that if the device is suspended for more than a certain amount of time upon turning it on the device turns off again.  I just found out that I am not the only one experiencing problems.  Over at Tilt Site (a subsite of the Mobility Site) users are reporting many of the same problems that I have experienced since the upgrade.  I’m not optimistic that another firmware update is forthcoming since AT&T must approve all firmware updates and they are planning to EOL (End of Life) the device. I may end up returning to the previous Windows Mobile 6.0 firmware image (so long threaded messages).

 

What Tools do I Need to Develop for Windows Mobile?

Several times in the past two weeks I’ve seen users on the MSDN forum ask what software tools are needed to develop for Windows Mobile.   It’s possible to develop for Windows Mobile devices using the .Net Compact Framework SDK and the command line compiler.  I would never suggest that some one do that; IDEs provide a much better debugging and development experience. The chart collowing this paragraph will let you know what versions of Visual Studio that you can use for each Windows Mobile and .Net version.  Note that no Visual Studio express version is lited here.

Visual Studio Version Supported Windows Mobile Versions
Visual Studio .Net 2003 Supports .Net Compact Framework 1.0 for Pocket PC 2002 and Windows Mobile 2003
Visual Studio 2005 Standard Edition or Better .Net 1.0 and .Net 2.0 from Windows Mobile 2003 to Windows Mobile 6
Visual Studio 2008 Professional .Net 2.0 and 3.5 from Windows Mobile 5 to Windows Mobile 6

Programs that you cannot presently use for Windows Mobile development include the express editions of Visual Studio and Visual Studio 2008 Standard.

 

SMS Economics

I was thinking of making a Windows Mobile multiplayer game using SMS.  One of the considerations is that not all of those playing will have an unlimited SMS plan so one must be thoughtful in minimizing the amount of SMS traffic that is generated by the game.

Let us assume for a moment that the 160 character limit is more than sufficient for transmitting all of the status information that needs to be known for the people playing in the game (I’t may not be, but I will address this later on. But ignore the message’s capacity for now).  One non-centralize method of ensuring that every one knows every one elses status is to have all the devices communicate with each other.  The number of messages needed to do this is dependent on the number of players.  Games ranging from 1 player to 5 players would require the following number of messages (note that the arrows represent a message being sent).

Number of Players Number of Messages Nodes and Arcs
1 0
2 2
3 6
4 12
5 20

The number of messages is increasing at a rather alarming rate. For n number of playeyers the number of messages needed can be calculated from the following equation.

Presently in the United States the price of a text message is 0.20 USD to 0.30 USD dependong on ones carrier.  I will use the midway point of 0.25 USD for calculating total cost.  Games written in this manner can quickly cost some one a significant amount of money.  When we calculate the total cost of these messages we must take into account that both the sender and the receiver of a message are charged.  So a message is collectivly costing the parties 0.50 USD.
Number of Players Cost of all messages
1 0.00 USD
2 1.00 USD
3 3.00 USD
4 6.00 USD
5 10.00 USD
6 15.00 USD
7 21.00 USD

At such an astronomical rate of cost growth the number of people allowed in a game will quickly become cost prohibitive. For a turned base game these would be the collective cost of each turn. A better model is needed.  Let’s consider a centralized model in which one player is designated the leader and all other players only communicate with the leader.  The leader will collect information from all players, accumulate it, then broadcast it to all players.

Number of Players Number of Messages Cost
1 0 0.00 USD
2 2 1.00 USD
3 6 3.00 USD
4 8 4.00 USD
5 10 5.00 USD
6 12 6.00 USD
7 14 7.00 USD

This organization looks deceptively better. The rate of growth for the messages is 2n and the total cost of the messages is n.Now if you consider the cost distribution you will see something unfair.  The leader takes on a large chunk of the cst.  50% of the cost to be exact.  Each one of the other players will only have a cost of 1.00 USD per turn.  Who would want to be leader under such an imbalanced Better balance may be achievable with a rotating leader assignment.

If the game being written for the phone is a turned based and thus the players are not taking their turns simultaneously then an even more economic SMS graph can be created.  Organize the players in a circuit.  Player one sends a message to player to, player to on to the next player, and continue this pathway until all players have received a message.  At the end of this pathway send a message back to player one. The cost per turn is finally capped!

Number of Players Messages Cost
1 0 0.00 USD
2 1 1.00 USD
3 1 1.00 USD
4 1 1.00 USD
5 1 1.00 USD
6 1 1.00 USD
7 1 1.00 USD

Notice that across all three models the communication in two player games is exactly the same.  For that reason I will suspend the idea of supporting more than two players (I may revisit it later).

I earlier mentioned that we are assuming that any data transmitted would fit in one message.  If we find that 2 or 3 messages are required to transmit a chunk of data then our message count and cost will increase linearly.  Being the last significant and the less complex part of the calculation I find it easier to leave that out until the end.

Next time around I will consider how much it cost to have a game with players that have no unlimited data plan.