What is the difference b/w Layer and Tier?

Sometimes people use them interchangeably but in my mind a layer is a logical separation (GUI, data access, business logic etc)and a tier is a physical separation (separate servers...ie web server, database server etc).

Tier is often used in reference to 3 tier applications (GUI, business objects/logic, database access), or n-tier applications. Often times in discussing a 3 tier application, someone will use "layer" when referring to one of the tiers, such as the "business layer" or "database access layer". They are often used interchangeably.

While there are probably technical definitions of these the differentiate them, I wouldn't get bogged down on it. Often times these terms take on a different flavor in different contexts.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.