Anna University
Fourth Semester 
Computer Science and Engineering 
CS2253 — COMPUTER ORGANIZATION AND ARCHITECTURE (Common to Information Technology) 

(Regulation 2008) 

Time: Three hours
Maximum: 100 Marks

Answer ALL Questions

PART A — (10 × 2 = 20 Marks)
1. Distinguish between autoincrement and autodecrement addressing mode.
2. Compare RISC with CISC architecture.
3. Under what situations the micro program counter is not incremented after a new instruction is fetched from micro program memory?
4. What are the relative merits of horizontal and vertical microinstruction format?
5. What is pipelining and what are the advantages of pipelining?
6. List the key aspects in gaining the performance in pipelined systems.
7. How many memory chips are needed to construct 2 M × 16 memory system using 512 K × 8 static memory chips?
8. What is virtual memory and what are the benefits of virtual memory?
9. What is meant by bus arbitration?
10. Name and give the purpose of widely used bus standard.

PART B — (5 × 16 = 80 Marks)

11. (a) (i) Describe the role of system software to improve the performance of a computer. (8) 

(ii) Design a 4-bit adder/subtracter circuit using full adders and explain its function. (8)


(b) (i) What are the special registers in a typical computer? Explain their purposes in detail. (8)
(ii) Design a 4-bit fast adder and explain its function in detail. (8)
12. (a) (i) Draw and explain the block diagram of a complete processor. (6) 
(ii) Briefly describe the design of a hardwired control unit. (10)
(b) (i) Explain the basic organization of a microprogrammed control  unit and the generation of control signals using microprogram. (12) 
(ii) What are the advantages and disadvantages of hardwired and microprogrammed control? (4)
13. (a) (i) Describe the role of cache memory in pipelined system. (8)
(ii) Discuss the influence of pipelining on instruction set design. (8)


(b) What is instruction hazard? Explain the methods for dealing with the instruction hazards. (16)

14. (a) (i) What are the different secondary storage devices? Elaborate on any one of the devices. (8)
(ii) Explain how the virtual address is converted into real address in a paged virtual memory system. (8)


(b) (i) Explain approaches for addressing multiple-module memory systems with suitable diagrams. (6)
(ii) Briefly describe magnetic disk principles and also the organization and accessing of data on a disk. (10)

15. (a) (i) Describe the hardware mechanism for handling multiple interrupt requests. (8)
(ii) What are handshaking signals? Explain the handshake control of data transfer during input and output operation. (8)
(b) (i) What are the needs for input-output interface? Explain the functions of a typical 8-bit parallel interface in detail. (10)
(ii) Describe the USB architecture with the help of a neat diagram. (6)