Mobile Operating Systems

In the market right now there are many type of OS on mobile phones. They can classified into two categories: open and proprietary.

Phone OS that are open has a public API that allow 3rd parties to write code on it. Most of them come with an SDK. Publishing the application after you write it is another matter that deserves an article by itself. The predominantly available open OS are:
- Symbian;
- Microsoft Windows Mobile;
- Linux; and
- Palm OS

Note that I made a distinction between OS and APIs. There are many ways you can write apps on phones using some public API, like J2ME and BREW. While you write some very sophisticated apps using these API, they are not OS. They lack many of the features of a full-blown OS. One very easy way to tell is to see if the API provides a means to write device drives. All the open OS I mentioned above provide means to write device drivers so that you can port them to hardware platform, although this information are mostly not open to the public.

There are many closed (aka proprietary) phone OS as well. Some are quite good, some are buggy, but that's not my point. I believe the future economy of scale in the mobile phone business favors open OS HUGELY.