CSS Computer Science 2018

PART - II SECTION - A

 

Q. No.2. (A)                          Briefly describe the functionality of the following CPU special-purpose registers: Instruction Register (IR), Memory Data Register (MDR)  and  Program Counter (PC).

(B)                               Differentiate between Address, Data and Control bus.

(C)                               Discuss instruction pipelining in the context of fetch-decode-execute cycle.

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Q. No.3. (A)              Differentiate between hub, bridge, switch and router.

(B)               Discuss how Network Address Translation (NAT) works and why is it useful?

(C)               Elaborate the working of multiplexing/de-multiplexing at the transport layer.

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Q. No.4. (A)    There are three processes PA, PB and PC and three resources RA, RB and RC. Resources RA and RB have one instance each while resource RC has two instances. PA is holding one instance of RC and has requested for RA. Process  PB is holding RA and has requested for RB. RB is allocated to PC which has also requested an instance of RC. Represent the scenario with a resource allocation graph. Discuss whether there is a deadlock or not? If yes, which processes are blocked?

(B)    In the context of Paging, consider the case where memory addresses are 32 bits

i.e. 20 bits Virtual Page Numbers and 12 bits of offset. How many virtual pages are there and what is the size of each page? Given the virtual address 0x7589, find the virtual page number and offset. If the respective page table entry contains 0x900DF, find the physical address.

(C) In the context of I/O management, differentiate between Pooling and Interrupts.

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Section - B

 

Q. No.5. (A)              Given two relations R and S, where R contains M tuples, S contains N tuples, and M >N > 0, give the minimum and maximum possible sizes (in tuples) for the resulting relation produced by each of the following relational algebra expressions.

i.                 R - S

ii.               R È S

iii.             R Ç S

iv.              R       S

(B)              Elaborate the concepts of super key, candidate key and foreign key with examples.

(C)              Discuss the difference between physical data independence and logical data independence.

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