Unity Pro Programming

Hi all, I'm a PLC beginner,I'm using Premium Hot standby Plc with Unity pro M software .I have few basic doubts regarding programming which are as follows
1. Why memory mapping is required? For example let’s say the field address is %I0.3.0.0 then why is it assigned to something like %MW500.0
2. Also why %MW is used, why not %M
3. While declaring the variable tags in Unity pro M, in the data type column there are types such as BOOL, EBOOL, INT, REAL, DINT. In this my understanding is that BOOL=Digital input, REAL=Analog input, INT=any numerical input,have my assumptions right?

4. In my program, even the digital inputs which are either (True=1 or false=0) are assigned to something like %MW501.X my doubt is why is it not assigned in %M
5. I see in my program only for EBOOL, %M is assigned (by the way what is EBOOL)
6. Also tell me for (DI, AI ,DO,AO) what we have to assign(%MW or %M or %I or %Q)

Thanks for any inputs!!

Analog addressing REAL data types in Unity Pro

Hello, I am having a similar problem regarding addressing analog inputs in Unity Pro with the data type REAL. If have a variable named ControlRmTemp where I assign an address %IW0.1.0 with data type REAL, why do I get an error saying "The topological type is incompatible"?
Thank you for any help.

The %IW data is in integer format and must be assigned as an integer. All you need to do is assign a tag to the %IW0.1.0 location then in a section of code use the instruction INT_TO_REAL and assign the output of this function to another tag of type Real.