Q: Is gem supports to all operating system? Is there any gem performance issue with operating system?
An application which is running perfectly in MAC OS is not working properly in Ubuntu.
Application is not throwing any error but some functionality & some layouts are not proper.
Any solution?
Please comment.
Thanks

A: OS
To answer your question properly, you have to remember that a gem is literally just a "plugin" for Ruby (& by virtue, Rails). This means that it will do nothing other than provide "pre-packaged" functionality you can use in your application
The problems you'll likely experience with operating systems will not be to do directly with the gem - instead it will be the interface of the gem with the operating system itself.
Let me explain...

Header Files
The primary issue for Gems is a lack of the appropriate header files on your operating system. 
Header files are basically the "class" files which various applications require to interface with different technologies:

Many programming languages and other computer files have a directive,
  often called include (as well as copy and import), that causes the
  contents of a second file to be inserted into the original file. These
  included files are called copybooks or header files. They are often
  used to define the physical layout of program data, pieces of
  procedural code and/or forward declarations while promoting
  encapsulation and the reuse of code.

This is especially true with Windows, but is also an issue on Linux & OSX too. The problem is that when you install a gem which relies on a third-party dependency (such as MYSQL or ImageMagick), or does something within the operating system itself (such as Resque), you can end up with issues.
The bottom-line to fixing these is to make sure your system uses the correct header files installed for the gem you wish to use.
--
Because different header files exist for different operating systems & gems, you'll have to be specific about your OS & gem in order to gain a workable response!
