How do assembly languages depend on operating systems?

Question

As An assembly language implements a symbolic representation of CPU instructions which are independent on OSes while assemblers are always running under some OS, I was wonde

Answer 1

The assembly language should be the same; as you point out, the instruction set depends only on the CPU and its architectural design. Where you start getting into trouble with different OSs, I believe, is when you start invoking e.g. interrupts (typically for I/O) which can definitely mean programs written for e.g. MSDOS won't work on e.g. Solaris (maybe a bad example).