I am new to MASM. So the questions may be quite basic.

When I am using the MASM assembler, there's an output file called "Link Map". Its content is composed of the starting offset and length of various segments, such as Data segment, Code segment and Stack segment. I am wondering that, where are these information describing? Are they talking about how various segments are located within an EXE file or, how segments are located within memory after the EXE file being loaded into memory by a program loader?

BTW: What does the "Assume" directive do? My understanding is that it tell the assembler to emit some information into the exe file header so the program loader could use it to set DS, CS, SS, ES register accordingly. Am I right on this?

Thanks in advance.