1. Windows7
1.1. pros:
1.1.1. it fixes many usability sins and adds consistency and polish to an interface that had too many rough edges.
1.1.2. Windows 7 uses less memory, runs fewer services, and consumes less disk space than its predecessor, Windows Vista, and in the 64-bit version it can address about five times more RAM than you can actually stuff onto a single motherboard.
1.1.3. Performance boost
1.2. cons:
1.2.1. Not free, restricted, no freedom
1.2.2. Because of the high usage, most spywares and viruses are targeted to this platform.
1.2.3. Not very stable – Windows is synonymous with the infamous "Blue screen of death"
2. Ubuntu
2.1. pros:
2.1.1. If Ubuntu can work well on every device users encounter (including non-Intel smartbooks and other new classes of portable devices that will be emerging in the next couple of years, displacing notebooks for many consumers), then name recognition will follow.
2.1.2. Option to “try before you install” using the Live CD feature
2.1.3. - Can easily install as a dual boot or even inside Windows using the Wubi installer
2.2. cons:
2.2.1. Unless you’re luck to get a CD, you do have to mess about with .ISO files and burn a disc. If you’re happy doing that, it’s not really a problem.
2.2.2. Many media formats that use proprietary DRM just won’t work on Ubuntu because of DRM restrictions
2.2.3. If you want to play DVDs then you need to resort to “Restricted” codecs
3. Operating System definition
3.1. software that controls the execution of computer programs and may provide various services
4. Chronium
4.1. pros:
4.2. cons:
5. Mac OS X
5.1. pros:
5.1.1. Excellent user interface and usability
5.1.2. Easy installation of applications
5.1.3. Targeted less by viruses & spywares
5.2. cons:
5.2.1. Though, based on open source operating systems, it is still proprietary.
5.2.2. The Operating system is limited to a specific platform
5.2.3. Cost of ownership is high – User is not free to try it out by paying for the operating system alone, instead the user is forced to buy new hardware at premium prices.