"1. VLSI technology
2. Embedded system
Problem is what is preferable RTOS or VLSI "

The above kind of suggests that RTOS = Embedded. This is far from true.

You have a point when you said that as faster and faster chips are evolving with focussed applications, the difference between them and RTOS is gradually becoming less pronounced.

If the question is VLSI or RTOS, I would go with VLSI.

If the question is VLSI or Embedded, I would marry Embedded and keep VLSI as a ... friend. OK you would have got the point!

Raghu