This is one of the top interview questions for testing, believe it or not. Yuva has the same answer as someone else on the web and they are both, not exactly correct. But then, he didn't quote it, so I guess he made it up.
San, if you do a Google on "What is installation shield?" you will find the only acceptable answer available.
We try not to answer interview questions.
Success is the ability to go from one failure to another with no loss of enthusiasm.
~ Winston Churchill ~