Mid-term Examination, October, 2001
			   CS 502 System Software
		   Marks : 50              Time : 2 hrs

Write brief answers

1. How will you classify a software as either an application software or a
   system software ? Give reasons to state that a text editor such as vi is a
   system software as well as an aplication software.			3 + 3

2. Why was assembly language invented ?					    4
   [Hint : What was the situation before and how was it improved by assembly
   languages ?]

3. Draw a block diagram to show the steps involved in a two-pass assembler,
   indicating where the important data structures are built and used. What
   are the various fields and their types in the different data structures ?
									8 + 5
   [Hint: First draw a rough sketch in half of the last page of your answer
   book]

4. What is lexical analysis ? What is a convenient method of creating an
   efficient lexical analyser (mention what you will have to do to create it)?
									3 + 4
5. Why is the macro feature provided in an assembly language ? How does it
   affect the size and efficiency of the machine language program generated ?
								        3 + 3

6. What are positional parameters, keyword parameters and expansion time
   variables in macros ? Give a smple example to show their usage.	6 + 2

7. What are some of the errors that an assembler should detect ? What course
   of action should the assembler take when it detects an error ?	3 + 3