try suse studio
yes, its abit basic but its good for an online free creator: jamstudio.com
AntiVir or AVG are two good free anti-virus programs.
the zte racer is really good! it has a operating system of android version 2.1! you can download over 50,000 free apps!
Yes, Windows XP Business was and still is a good operating system. As of today 78% of business still use Windows XP as their primary operating system.
visit this page that will give you a good idea about operating system
A good course to take if you want to develop an operating system is a course in "Operating Systems".
Ubuntu is a solid Virus free operating system. It gets updates on a daily bases with a new version out every 6 months. Its all free and works fast with a huge community of support behind you to help you out with any problems. All software and download are free and all can be downloaded within the operating system. Couple of clicks and its installed with no effort. The operating system can be customised into almost anything you can imagtion. There is nothing you cant change.
Pros are good things about something. Cons are bad things about something. So the pros and cons of an operating system are the good and bad things about it.
Yes, you should always try to optimize your operating system. This includes defragging and removing viruses and malware from the system.
You can download free vmware images of operating systems if you search on google. For example there are two good free operating systems, first you can download ubuntu from linux or chrome os.
The Linux From Scratch tutorial is available online.
Yes, the Kitkat Android version is a good operating system.