CS501 Final Term Solved Subjective with References by Moaaz

Solved Subjective · From Midterm Papers · FEB 09,2013 · PSMD01

Q1. Define PROM? (2 marks)

Answer: (Page 356) The PROM stands for Programmable Read only Memory. It is also nonvolatile and may be written into only once. For PROM, the writing process is performed electrically in the field. PROMs provide flexibility and convenience.

Q2. How we refer the register to the RTL? Give an example? (2 marks)

Answer: (Page 66)

Specifying Registers

The format used to specify registers is Register Name<register bits> For example, IR<31..0> means bits numbered 31 to 0 of a 32-bit register named “IR” (Instruction Register).

Q3. What is the use of modem? (2 marks)

Answer: (Page 391) To interconnect different computers by using twisted pair copper wire, an interface is used which is called modem. Modem stands for modulation/demodulation. Modems are very useful to utilize the telephone network (i.e. 4 KHz bandwidth) for data and voice transmission.

Q4. What is the advantage of RAID level 0? (2 marks)

Answer: (Page 330)

• The user and system data are distributed across all the disks in the array.
• Notable advantage over the use of a single large disk.

Q6. Encode the register into binary? R0 TO R7 (3 marks)

Answer: (Page 51)

Encoding of the General Purpose

Registers. R0 00000 R1 00001 R2 00010 R3 00011 R4 00100 R5 00101 R6 00110 R7 00111

Q7. What is the difference multimode fiber and mono fiber which are used as a physical medium of the network? (3 marks)

Answer: (Page 391)

Multimode fiber

This fiber has large diameter. When light is injected, it disperses, so the effective data rate decreases. Multimode fiber is used as a physical medium of the network

Mono mode Fiber

Its diameter is very small. So dispersion is small and data rate is very high.

Q8. What is meant by cycle stealing in the DMA? (3 marks)

Answer: (Page 320) The DMA module takes control of the bus to transfer data to and from memory by forcing the CPU to temporarily suspend its operation. This approach is called Cycle Stealing because in this approach DMA steals a bus cycle.

Q10. Write the radix conversion algorithm to convert 39210 to the base 16? (5 marks)

Answer: (Page 335) According to the above algorithm 390/16 =24( rem=6), x0=6 24/16= 1(rem=8), x1=8, x2=1 Thus 39010 =18616

Q11. What is the difference between internal segmentation and external segmentation relevant to the computer storage? (5 marks)

Answer: In fixed partitioning the pages are of fixed size and some space is wasted in the last page. For example if we have page size equal to 2 K and the program size is of 9 K than we have to use 5 pages each of size 2 k. In this case 4 pages fully consumed but the last page has 1 k free memory and it can not be utilized, so this type of fragmentation is called internal fragmentation. It is basically the wastage of space of within the partition. In variable partitioning the page size is not fixed. In this type of partitioning the page size is variable. So pages are allocated accordingly. If say program A is of size 5 k than 5 k page size is reserved and say another program B comes in having size 3 k so now page size of 3 k is reserved. Now if A program exits and the new program C having size 4 k comes in, it will replace the 5 k partition of program A but the space of 1 K is wasted between program C and program B. This wastage of space is called external fragmentation. It is basically the wastage of space between the partitions.

Q12. Write the SRC assembly program for the following expression? (5 marks)

Z= 16(a+b)-32(c-58)

Answer: (According to Page 57)

subi R3, R1, 58 ; R3 contains (c-58) shl R7, R3, 5 ; R7 contains 32(c-58) ld R4, a ld R5, b add R6, R4, R5 ; R6 contains (a+b) shl R8, R6, 4 ; R8 contains 16(a+b) sub R9, R7, R8 ; the result is in R9

Q1. Write two lines on connection oriented communication? 2

Answer: (Page 394) In this method, same path is always taken for the transfer of messages. It reserves the bandwidth until the transfer is complete. So no other server could use that path until it becomes free.

Q2. What is the advantage of direct cache memory? 2

Answer: (Page 361) Advantage is Simplicity.