CS501 Current Final Term Fall 2013 Shared by Moona_Fatima File 4

aoa this is my todays paper

mcQs mostly new the about 15 mooaz bahi ki file me se aye the 

long qs ans k sath past ker rhy hoon 

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.

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.  Find the average relational latency if the disk octet 15000rpm. (3 marks ) Answer:- (Page 324) The average latency to the desired data is halfway round the disk so Average rotational latency = (1 / (RPM / 60)) * 0.5 * 1000 = 30000 / RPM = 30000 / 15000 =2ms  How many platters are required for a 40GB disk if there are 1024 bytes/sector, 2048 sectors per track and 4096 tracks per platter? (5 marks) Answer:- (Page 325) The capacity of one platter = 1024 x 2048 x 4096 = 8GB For a 40GB hard disk, we need 40/8 = 5 such platters.  why we use matrix in decoder Answer:- (Page 352) A typical one level decoder has n inputs and 2n output, using one level of gates, each with a fan-in of n. Two level decoders are limited in size because of high gate fan-in. In order to reduce the gate fan-in to a value of 8 or 6, tree and matrix decoders are utilized.  difference bw connection oriented and connection less Answer:- (Page 394) Connection Oriented Communication • 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. • Telephone exchange and circuit switching is the example of connection oriented communication. Connection less Communication • Here message is divided into packets with each packet having destination address. • Each packet can take different path and reach the destination from any route by looking at its address. • Postal system and packet switching are examples of connection less communication  Frndz ik control signals se related q tha k wo three types k hoty hain app ko un k name likhny hain n koi sy 2 ko define kerna hy. Ik q tha us me ye kha gya tha k app ko ye reasons se batana hy k DMA better I/O units ko control kerta hy connected to cpu. Ik numerical thaw o mjy sai se yaad nhy reha .

Frndz ik last lec me paging or page size n page tables ka hy us ka 5 num ka q tha,